Copy of LED Dimmer Circuit using 555 Timer - on Wed, 07/05/2023 - 10:40 User-1688735416Designer247277 × User-1688735416 Member for 8 months 2 weeks 9 designs 1 groups Title Description <p>This LED Dimmer Circuit uses a 555 Timer to control the PWM duty cycle of the current drive. Rather than apply proportional but continuous current to the LED for dimming, which can cause color shifts, modulating the duty cycle allows the LED to operate at its nominal current during the “ON” portion of the cycle. Because the frequency response of human vision is limited, using a PWM frequency of 250 Hz avoids the perception of flicker for the observer.</p> <p>The LED model has an internal monitor for the "perceived" light output (blue waveform), which is a low-pass filtered version of the instantaneous light output. The filter pole frequency is set to 15 Hz to represent the bandwidth of the human eye. The value of the dimmer setting (green waveform) is increased from 10% to 90% at time 100msec. The LED current pulses (red waveform) are shown before and after the duty-cycle transition.</p> <p>Part of this design is based on a dimmer schematic found on-line:</p> <p><a href="http://www.555-timer-circuits.com/led-dimmer.html">http://www.555-timer-circuits.com/led-dimmer.html</a></p> <p>That original circuit is actually incorrect, one of the diodes connected to pin 7 on the 555-Timer needs to be reversed. There was a comment from a reader who said he built the circuit as shown and it didn’t work. This is a good example of the value of simulating circuits before building hardware!</p> About text formats Tags 555 TimerLEDpotentiometer Select a tag from the list or create your own.Drag to re-order taxonomy terms. License - None - What's this? Design Titleby User-1688735416 × Embed Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/embed-design/600440"></iframe> Embed Live Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/node/600440"></iframe> Share a Link Copy URL https://explore.partquest.com/node/600440 Copy of LED Dimmer Circuit using 555 Timer - on Wed, 07/05/2023 - 10:40 User-1688735416Designer247277 × User-1688735416 Member for 8 months 2 weeks 9 designs 1 groups Title Description <p>This LED Dimmer Circuit uses a 555 Timer to control the PWM duty cycle of the current drive. Rather than apply proportional but continuous current to the LED for dimming, which can cause color shifts, modulating the duty cycle allows the LED to operate at its nominal current during the “ON” portion of the cycle. Because the frequency response of human vision is limited, using a PWM frequency of 250 Hz avoids the perception of flicker for the observer.</p> <p>The LED model has an internal monitor for the "perceived" light output (blue waveform), which is a low-pass filtered version of the instantaneous light output. The filter pole frequency is set to 15 Hz to represent the bandwidth of the human eye. The value of the dimmer setting (green waveform) is increased from 10% to 90% at time 100msec. The LED current pulses (red waveform) are shown before and after the duty-cycle transition.</p> <p>Part of this design is based on a dimmer schematic found on-line:</p> <p><a href="http://www.555-timer-circuits.com/led-dimmer.html">http://www.555-timer-circuits.com/led-dimmer.html</a></p> <p>That original circuit is actually incorrect, one of the diodes connected to pin 7 on the 555-Timer needs to be reversed. There was a comment from a reader who said he built the circuit as shown and it didn’t work. This is a good example of the value of simulating circuits before building hardware!</p> About text formats Tags 555 TimerLEDpotentiometer Select a tag from the list or create your own.Drag to re-order taxonomy terms. License - None - What's this? Design Titleby User-1688735416 × Embed Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/embed-design/600435"></iframe> Embed Live Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/node/600435"></iframe> Share a Link Copy URL https://explore.partquest.com/node/600435 Copy of Voltage divider circuit using potentiometer - on Tue, 01/26/2021 - 14:40 atila.aires2Designer242452 × atila.aires2 Member for 2 years 3 months 7 designs 1 groups Title Description <p>A simple example created to provide an example for a forum post on All About Circuits:</p> <p>http://forum.allaboutcircuits.com/threads/ltspice-problem-with-varying-parameters.117229/#post-945807</p> About text formats Tags potentiometerAAC Select a tag from the list or create your own.Drag to re-order taxonomy terms. License - None - What's this? Design Titleby atila.aires2 × Embed Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/embed-design/511098"></iframe> Embed Live Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/node/511098"></iframe> Share a Link Copy URL https://explore.partquest.com/node/511098 Copy of Voltage divider circuit using potentiometer - on Mon, 03/01/2021 - 00:47 rayane2gadelha5Designer238057 × rayane2gadelha5 Member for 3 years 1 month 56 designs 2 groups Title Description <p>A simple example created to provide an example for a forum post on All About Circuits:</p> <p>http://forum.allaboutcircuits.com/threads/ltspice-problem-with-varying-parameters.117229/#post-945807</p> About text formats Tags potentiometerAAC Select a tag from the list or create your own.Drag to re-order taxonomy terms. License - None - What's this? Design Titleby rayane2gadelha5 × Embed Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/embed-design/414864"></iframe> Embed Live Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/node/414864"></iframe> Share a Link Copy URL https://explore.partquest.com/node/414864 Copy of LED Dimmer Circuit using 555 Timer - on Wed, 01/13/2021 - 19:51 anoorDesigner237496 × anoor Member for 3 years 2 months 0 designs 1 groups Title Description <p>This LED Dimmer Circuit uses a 555 Timer to control the PWM duty cycle of the current drive. Rather than apply proportional but continuous current to the LED for dimming, which can cause color shifts, modulating the duty cycle allows the LED to operate at its nominal current during the “ON” portion of the cycle. Because the frequency response of human vision is limited, using a PWM frequency of 250 Hz avoids the perception of flicker for the observer.</p> <p>The LED model has an internal monitor for the "perceived" light output (blue waveform), which is a low-pass filtered version of the instantaneous light output. The filter pole frequency is set to 15 Hz to represent the bandwidth of the human eye. The value of the dimmer setting (green waveform) is increased from 10% to 90% at time 100msec. The LED current pulses (red waveform) are shown before and after the duty-cycle transition.</p> <p>Part of this design is based on a dimmer schematic found on-line:</p> <p><a href="http://www.555-timer-circuits.com/led-dimmer.html">http://www.555-timer-circuits.com/led-dimmer.html</a></p> <p>That original circuit is actually incorrect, one of the diodes connected to pin 7 on the 555-Timer needs to be reversed. There was a comment from a reader who said he built the circuit as shown and it didn’t work. This is a good example of the value of simulating circuits before building hardware!</p> About text formats Tags 555 TimerLEDpotentiometer Select a tag from the list or create your own.Drag to re-order taxonomy terms. License - None - What's this? Design Titleby anoor × Embed Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/embed-design/402065"></iframe> Embed Live Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/node/402065"></iframe> Share a Link Copy URL https://explore.partquest.com/node/402065 Copy of LED Dimmer Circuit using 555 Timer - on Wed, 01/13/2021 - 19:51 anoorDesigner237496 × anoor Member for 3 years 2 months 0 designs 1 groups Title Description <p>This LED Dimmer Circuit uses a 555 Timer to control the PWM duty cycle of the current drive. Rather than apply proportional but continuous current to the LED for dimming, which can cause color shifts, modulating the duty cycle allows the LED to operate at its nominal current during the “ON” portion of the cycle. Because the frequency response of human vision is limited, using a PWM frequency of 250 Hz avoids the perception of flicker for the observer.</p> <p>The LED model has an internal monitor for the "perceived" light output (blue waveform), which is a low-pass filtered version of the instantaneous light output. The filter pole frequency is set to 15 Hz to represent the bandwidth of the human eye. The value of the dimmer setting (green waveform) is increased from 10% to 90% at time 100msec. The LED current pulses (red waveform) are shown before and after the duty-cycle transition.</p> <p>Part of this design is based on a dimmer schematic found on-line:</p> <p><a href="http://www.555-timer-circuits.com/led-dimmer.html">http://www.555-timer-circuits.com/led-dimmer.html</a></p> <p>That original circuit is actually incorrect, one of the diodes connected to pin 7 on the 555-Timer needs to be reversed. There was a comment from a reader who said he built the circuit as shown and it didn’t work. This is a good example of the value of simulating circuits before building hardware!</p> About text formats Tags 555 TimerLEDpotentiometer Select a tag from the list or create your own.Drag to re-order taxonomy terms. License - None - What's this? Design Titleby anoor × Embed Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/embed-design/402064"></iframe> Embed Live Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/node/402064"></iframe> Share a Link Copy URL https://explore.partquest.com/node/402064 Copy of LED Dimmer Circuit using 555 Timer - on Wed, 01/13/2021 - 19:51 anoorDesigner237496 × anoor Member for 3 years 2 months 0 designs 1 groups Title Description <p>This LED Dimmer Circuit uses a 555 Timer to control the PWM duty cycle of the current drive. Rather than apply proportional but continuous current to the LED for dimming, which can cause color shifts, modulating the duty cycle allows the LED to operate at its nominal current during the “ON” portion of the cycle. Because the frequency response of human vision is limited, using a PWM frequency of 250 Hz avoids the perception of flicker for the observer.</p> <p>The LED model has an internal monitor for the "perceived" light output (blue waveform), which is a low-pass filtered version of the instantaneous light output. The filter pole frequency is set to 15 Hz to represent the bandwidth of the human eye. The value of the dimmer setting (green waveform) is increased from 10% to 90% at time 100msec. The LED current pulses (red waveform) are shown before and after the duty-cycle transition.</p> <p>Part of this design is based on a dimmer schematic found on-line:</p> <p><a href="http://www.555-timer-circuits.com/led-dimmer.html">http://www.555-timer-circuits.com/led-dimmer.html</a></p> <p>That original circuit is actually incorrect, one of the diodes connected to pin 7 on the 555-Timer needs to be reversed. There was a comment from a reader who said he built the circuit as shown and it didn’t work. This is a good example of the value of simulating circuits before building hardware!</p> About text formats Tags 555 TimerLEDpotentiometer Select a tag from the list or create your own.Drag to re-order taxonomy terms. License - None - What's this? Design Titleby anoor × Embed Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/embed-design/402063"></iframe> Embed Live Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/node/402063"></iframe> Share a Link Copy URL https://explore.partquest.com/node/402063 Copy of LED Dimmer Circuit - on Thu, 01/07/2021 - 11:15 sami.jaberDesigner237221 × sami.jaber Member for 3 years 3 months 1 designs 1 groups Title Description <p>This LED Dimmer Circuit uses a 555 Timer to control the PWM duty cycle of the current drive. Rather than apply proportional but continuous current to the LED for dimming, which can cause color shifts, modulating the duty cycle allows the LED to operate at its nominal current during the “ON” portion of the cycle. Because the frequency response of human vision is limited, using a PWM frequency of 250 Hz avoids the perception of flicker for the observer.</p> <p>The LED model has an internal monitor for the "perceived" light output (blue waveform), which is a low-pass filtered version of the instantaneous light output. The filter pole frequency is set to 15 Hz to represent the bandwidth of the human eye. The value of the potentiometer setting (green waveform), which closely approximates the PWM duty-cycle, is increased from 10% to 90% at time 50msec. The LED current pulses (red waveform) are shown before and after that duty-cycle transition.</p> About text formats Tags 555 TimerLEDpotentiometer Select a tag from the list or create your own.Drag to re-order taxonomy terms. License - None - What's this? Design Titleby sami.jaber × Embed Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/embed-design/398853"></iframe> Embed Live Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/node/398853"></iframe> Share a Link Copy URL https://explore.partquest.com/node/398853 LED Dimmer Circuit - on Thu, 01/07/2021 - 17:56 tingwei0116Designer236121 × tingwei0116 Member for 3 years 5 months 8 designs 1 groups Title Description <p>This LED Dimmer Circuit uses a 555 Timer to control the PWM duty cycle of the current drive. Rather than apply proportional but continuous current to the LED for dimming, which can cause color shifts, modulating the duty cycle allows the LED to operate at its nominal current during the “ON” portion of the cycle. Because the frequency response of human vision is limited, using a PWM frequency of 250 Hz avoids the perception of flicker for the observer.</p> <p>The LED model has an internal monitor for the "perceived" light output (blue waveform), which is a low-pass filtered version of the instantaneous light output. The filter pole frequency is set to 15 Hz to represent the bandwidth of the human eye. The value of the potentiometer setting (green waveform), which closely approximates the PWM duty-cycle, is increased from 10% to 90% at time 50msec. The LED current pulses (red waveform) are shown before and after that duty-cycle transition.</p> About text formats Tags 555 TimerLEDpotentiometer Select a tag from the list or create your own.Drag to re-order taxonomy terms. License - None - What's this? Design Titleby tingwei0116 × Embed Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/embed-design/398836"></iframe> Embed Live Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/node/398836"></iframe> Share a Link Copy URL https://explore.partquest.com/node/398836 Copy of LED Dimmer Circuit using 555 Timer - on Wed, 12/30/2020 - 16:44 usman.qasim1994Designer237332 × usman.qasim1994 Member for 3 years 2 months 0 designs 1 groups Title Description <p>This LED Dimmer Circuit uses a 555 Timer to control the PWM duty cycle of the current drive. Rather than apply proportional but continuous current to the LED for dimming, which can cause color shifts, modulating the duty cycle allows the LED to operate at its nominal current during the “ON” portion of the cycle. Because the frequency response of human vision is limited, using a PWM frequency of 250 Hz avoids the perception of flicker for the observer.</p> <p>The LED model has an internal monitor for the "perceived" light output (blue waveform), which is a low-pass filtered version of the instantaneous light output. The filter pole frequency is set to 15 Hz to represent the bandwidth of the human eye. The value of the dimmer setting (green waveform) is increased from 10% to 90% at time 100msec. The LED current pulses (red waveform) are shown before and after the duty-cycle transition.</p> <p>Part of this design is based on a dimmer schematic found on-line:</p> <p><a href="http://www.555-timer-circuits.com/led-dimmer.html">http://www.555-timer-circuits.com/led-dimmer.html</a></p> <p>That original circuit is actually incorrect, one of the diodes connected to pin 7 on the 555-Timer needs to be reversed. There was a comment from a reader who said he built the circuit as shown and it didn’t work. This is a good example of the value of simulating circuits before building hardware!</p> About text formats Tags 555 TimerLEDpotentiometer Select a tag from the list or create your own.Drag to re-order taxonomy terms. License - None - What's this? Design Titleby usman.qasim1994 × Embed Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/embed-design/397033"></iframe> Embed Live Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/node/397033"></iframe> Share a Link Copy URL https://explore.partquest.com/node/397033 Pagination Previous page ‹‹ Page 2 Next page ››
Copy of LED Dimmer Circuit using 555 Timer - on Wed, 07/05/2023 - 10:40 User-1688735416Designer247277 × User-1688735416 Member for 8 months 2 weeks 9 designs 1 groups Title Description <p>This LED Dimmer Circuit uses a 555 Timer to control the PWM duty cycle of the current drive. Rather than apply proportional but continuous current to the LED for dimming, which can cause color shifts, modulating the duty cycle allows the LED to operate at its nominal current during the “ON” portion of the cycle. Because the frequency response of human vision is limited, using a PWM frequency of 250 Hz avoids the perception of flicker for the observer.</p> <p>The LED model has an internal monitor for the "perceived" light output (blue waveform), which is a low-pass filtered version of the instantaneous light output. The filter pole frequency is set to 15 Hz to represent the bandwidth of the human eye. The value of the dimmer setting (green waveform) is increased from 10% to 90% at time 100msec. The LED current pulses (red waveform) are shown before and after the duty-cycle transition.</p> <p>Part of this design is based on a dimmer schematic found on-line:</p> <p><a href="http://www.555-timer-circuits.com/led-dimmer.html">http://www.555-timer-circuits.com/led-dimmer.html</a></p> <p>That original circuit is actually incorrect, one of the diodes connected to pin 7 on the 555-Timer needs to be reversed. There was a comment from a reader who said he built the circuit as shown and it didn’t work. This is a good example of the value of simulating circuits before building hardware!</p> About text formats Tags 555 TimerLEDpotentiometer Select a tag from the list or create your own.Drag to re-order taxonomy terms. License - None - What's this? Design Titleby User-1688735416 × Embed Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/embed-design/600435"></iframe> Embed Live Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/node/600435"></iframe> Share a Link Copy URL https://explore.partquest.com/node/600435 Copy of Voltage divider circuit using potentiometer - on Tue, 01/26/2021 - 14:40 atila.aires2Designer242452 × atila.aires2 Member for 2 years 3 months 7 designs 1 groups Title Description <p>A simple example created to provide an example for a forum post on All About Circuits:</p> <p>http://forum.allaboutcircuits.com/threads/ltspice-problem-with-varying-parameters.117229/#post-945807</p> About text formats Tags potentiometerAAC Select a tag from the list or create your own.Drag to re-order taxonomy terms. License - None - What's this? Design Titleby atila.aires2 × Embed Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/embed-design/511098"></iframe> Embed Live Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/node/511098"></iframe> Share a Link Copy URL https://explore.partquest.com/node/511098 Copy of Voltage divider circuit using potentiometer - on Mon, 03/01/2021 - 00:47 rayane2gadelha5Designer238057 × rayane2gadelha5 Member for 3 years 1 month 56 designs 2 groups Title Description <p>A simple example created to provide an example for a forum post on All About Circuits:</p> <p>http://forum.allaboutcircuits.com/threads/ltspice-problem-with-varying-parameters.117229/#post-945807</p> About text formats Tags potentiometerAAC Select a tag from the list or create your own.Drag to re-order taxonomy terms. License - None - What's this? Design Titleby rayane2gadelha5 × Embed Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/embed-design/414864"></iframe> Embed Live Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/node/414864"></iframe> Share a Link Copy URL https://explore.partquest.com/node/414864 Copy of LED Dimmer Circuit using 555 Timer - on Wed, 01/13/2021 - 19:51 anoorDesigner237496 × anoor Member for 3 years 2 months 0 designs 1 groups Title Description <p>This LED Dimmer Circuit uses a 555 Timer to control the PWM duty cycle of the current drive. Rather than apply proportional but continuous current to the LED for dimming, which can cause color shifts, modulating the duty cycle allows the LED to operate at its nominal current during the “ON” portion of the cycle. Because the frequency response of human vision is limited, using a PWM frequency of 250 Hz avoids the perception of flicker for the observer.</p> <p>The LED model has an internal monitor for the "perceived" light output (blue waveform), which is a low-pass filtered version of the instantaneous light output. The filter pole frequency is set to 15 Hz to represent the bandwidth of the human eye. The value of the dimmer setting (green waveform) is increased from 10% to 90% at time 100msec. The LED current pulses (red waveform) are shown before and after the duty-cycle transition.</p> <p>Part of this design is based on a dimmer schematic found on-line:</p> <p><a href="http://www.555-timer-circuits.com/led-dimmer.html">http://www.555-timer-circuits.com/led-dimmer.html</a></p> <p>That original circuit is actually incorrect, one of the diodes connected to pin 7 on the 555-Timer needs to be reversed. There was a comment from a reader who said he built the circuit as shown and it didn’t work. This is a good example of the value of simulating circuits before building hardware!</p> About text formats Tags 555 TimerLEDpotentiometer Select a tag from the list or create your own.Drag to re-order taxonomy terms. License - None - What's this? Design Titleby anoor × Embed Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/embed-design/402065"></iframe> Embed Live Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/node/402065"></iframe> Share a Link Copy URL https://explore.partquest.com/node/402065 Copy of LED Dimmer Circuit using 555 Timer - on Wed, 01/13/2021 - 19:51 anoorDesigner237496 × anoor Member for 3 years 2 months 0 designs 1 groups Title Description <p>This LED Dimmer Circuit uses a 555 Timer to control the PWM duty cycle of the current drive. Rather than apply proportional but continuous current to the LED for dimming, which can cause color shifts, modulating the duty cycle allows the LED to operate at its nominal current during the “ON” portion of the cycle. Because the frequency response of human vision is limited, using a PWM frequency of 250 Hz avoids the perception of flicker for the observer.</p> <p>The LED model has an internal monitor for the "perceived" light output (blue waveform), which is a low-pass filtered version of the instantaneous light output. The filter pole frequency is set to 15 Hz to represent the bandwidth of the human eye. The value of the dimmer setting (green waveform) is increased from 10% to 90% at time 100msec. The LED current pulses (red waveform) are shown before and after the duty-cycle transition.</p> <p>Part of this design is based on a dimmer schematic found on-line:</p> <p><a href="http://www.555-timer-circuits.com/led-dimmer.html">http://www.555-timer-circuits.com/led-dimmer.html</a></p> <p>That original circuit is actually incorrect, one of the diodes connected to pin 7 on the 555-Timer needs to be reversed. There was a comment from a reader who said he built the circuit as shown and it didn’t work. This is a good example of the value of simulating circuits before building hardware!</p> About text formats Tags 555 TimerLEDpotentiometer Select a tag from the list or create your own.Drag to re-order taxonomy terms. License - None - What's this? Design Titleby anoor × Embed Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/embed-design/402064"></iframe> Embed Live Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/node/402064"></iframe> Share a Link Copy URL https://explore.partquest.com/node/402064 Copy of LED Dimmer Circuit using 555 Timer - on Wed, 01/13/2021 - 19:51 anoorDesigner237496 × anoor Member for 3 years 2 months 0 designs 1 groups Title Description <p>This LED Dimmer Circuit uses a 555 Timer to control the PWM duty cycle of the current drive. Rather than apply proportional but continuous current to the LED for dimming, which can cause color shifts, modulating the duty cycle allows the LED to operate at its nominal current during the “ON” portion of the cycle. Because the frequency response of human vision is limited, using a PWM frequency of 250 Hz avoids the perception of flicker for the observer.</p> <p>The LED model has an internal monitor for the "perceived" light output (blue waveform), which is a low-pass filtered version of the instantaneous light output. The filter pole frequency is set to 15 Hz to represent the bandwidth of the human eye. The value of the dimmer setting (green waveform) is increased from 10% to 90% at time 100msec. The LED current pulses (red waveform) are shown before and after the duty-cycle transition.</p> <p>Part of this design is based on a dimmer schematic found on-line:</p> <p><a href="http://www.555-timer-circuits.com/led-dimmer.html">http://www.555-timer-circuits.com/led-dimmer.html</a></p> <p>That original circuit is actually incorrect, one of the diodes connected to pin 7 on the 555-Timer needs to be reversed. There was a comment from a reader who said he built the circuit as shown and it didn’t work. This is a good example of the value of simulating circuits before building hardware!</p> About text formats Tags 555 TimerLEDpotentiometer Select a tag from the list or create your own.Drag to re-order taxonomy terms. License - None - What's this? Design Titleby anoor × Embed Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/embed-design/402063"></iframe> Embed Live Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/node/402063"></iframe> Share a Link Copy URL https://explore.partquest.com/node/402063 Copy of LED Dimmer Circuit - on Thu, 01/07/2021 - 11:15 sami.jaberDesigner237221 × sami.jaber Member for 3 years 3 months 1 designs 1 groups Title Description <p>This LED Dimmer Circuit uses a 555 Timer to control the PWM duty cycle of the current drive. Rather than apply proportional but continuous current to the LED for dimming, which can cause color shifts, modulating the duty cycle allows the LED to operate at its nominal current during the “ON” portion of the cycle. Because the frequency response of human vision is limited, using a PWM frequency of 250 Hz avoids the perception of flicker for the observer.</p> <p>The LED model has an internal monitor for the "perceived" light output (blue waveform), which is a low-pass filtered version of the instantaneous light output. The filter pole frequency is set to 15 Hz to represent the bandwidth of the human eye. The value of the potentiometer setting (green waveform), which closely approximates the PWM duty-cycle, is increased from 10% to 90% at time 50msec. The LED current pulses (red waveform) are shown before and after that duty-cycle transition.</p> About text formats Tags 555 TimerLEDpotentiometer Select a tag from the list or create your own.Drag to re-order taxonomy terms. License - None - What's this? Design Titleby sami.jaber × Embed Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/embed-design/398853"></iframe> Embed Live Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/node/398853"></iframe> Share a Link Copy URL https://explore.partquest.com/node/398853 LED Dimmer Circuit - on Thu, 01/07/2021 - 17:56 tingwei0116Designer236121 × tingwei0116 Member for 3 years 5 months 8 designs 1 groups Title Description <p>This LED Dimmer Circuit uses a 555 Timer to control the PWM duty cycle of the current drive. Rather than apply proportional but continuous current to the LED for dimming, which can cause color shifts, modulating the duty cycle allows the LED to operate at its nominal current during the “ON” portion of the cycle. Because the frequency response of human vision is limited, using a PWM frequency of 250 Hz avoids the perception of flicker for the observer.</p> <p>The LED model has an internal monitor for the "perceived" light output (blue waveform), which is a low-pass filtered version of the instantaneous light output. The filter pole frequency is set to 15 Hz to represent the bandwidth of the human eye. The value of the potentiometer setting (green waveform), which closely approximates the PWM duty-cycle, is increased from 10% to 90% at time 50msec. The LED current pulses (red waveform) are shown before and after that duty-cycle transition.</p> About text formats Tags 555 TimerLEDpotentiometer Select a tag from the list or create your own.Drag to re-order taxonomy terms. License - None - What's this? Design Titleby tingwei0116 × Embed Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/embed-design/398836"></iframe> Embed Live Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/node/398836"></iframe> Share a Link Copy URL https://explore.partquest.com/node/398836 Copy of LED Dimmer Circuit using 555 Timer - on Wed, 12/30/2020 - 16:44 usman.qasim1994Designer237332 × usman.qasim1994 Member for 3 years 2 months 0 designs 1 groups Title Description <p>This LED Dimmer Circuit uses a 555 Timer to control the PWM duty cycle of the current drive. Rather than apply proportional but continuous current to the LED for dimming, which can cause color shifts, modulating the duty cycle allows the LED to operate at its nominal current during the “ON” portion of the cycle. Because the frequency response of human vision is limited, using a PWM frequency of 250 Hz avoids the perception of flicker for the observer.</p> <p>The LED model has an internal monitor for the "perceived" light output (blue waveform), which is a low-pass filtered version of the instantaneous light output. The filter pole frequency is set to 15 Hz to represent the bandwidth of the human eye. The value of the dimmer setting (green waveform) is increased from 10% to 90% at time 100msec. The LED current pulses (red waveform) are shown before and after the duty-cycle transition.</p> <p>Part of this design is based on a dimmer schematic found on-line:</p> <p><a href="http://www.555-timer-circuits.com/led-dimmer.html">http://www.555-timer-circuits.com/led-dimmer.html</a></p> <p>That original circuit is actually incorrect, one of the diodes connected to pin 7 on the 555-Timer needs to be reversed. There was a comment from a reader who said he built the circuit as shown and it didn’t work. This is a good example of the value of simulating circuits before building hardware!</p> About text formats Tags 555 TimerLEDpotentiometer Select a tag from the list or create your own.Drag to re-order taxonomy terms. License - None - What's this? Design Titleby usman.qasim1994 × Embed Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/embed-design/397033"></iframe> Embed Live Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/node/397033"></iframe> Share a Link Copy URL https://explore.partquest.com/node/397033 Pagination Previous page ‹‹ Page 2 Next page ››
Copy of Voltage divider circuit using potentiometer - on Tue, 01/26/2021 - 14:40 atila.aires2Designer242452 × atila.aires2 Member for 2 years 3 months 7 designs 1 groups Title Description <p>A simple example created to provide an example for a forum post on All About Circuits:</p> <p>http://forum.allaboutcircuits.com/threads/ltspice-problem-with-varying-parameters.117229/#post-945807</p> About text formats Tags potentiometerAAC Select a tag from the list or create your own.Drag to re-order taxonomy terms. License - None - What's this? Design Titleby atila.aires2 × Embed Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/embed-design/511098"></iframe> Embed Live Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/node/511098"></iframe> Share a Link Copy URL https://explore.partquest.com/node/511098 Copy of Voltage divider circuit using potentiometer - on Mon, 03/01/2021 - 00:47 rayane2gadelha5Designer238057 × rayane2gadelha5 Member for 3 years 1 month 56 designs 2 groups Title Description <p>A simple example created to provide an example for a forum post on All About Circuits:</p> <p>http://forum.allaboutcircuits.com/threads/ltspice-problem-with-varying-parameters.117229/#post-945807</p> About text formats Tags potentiometerAAC Select a tag from the list or create your own.Drag to re-order taxonomy terms. License - None - What's this? Design Titleby rayane2gadelha5 × Embed Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/embed-design/414864"></iframe> Embed Live Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/node/414864"></iframe> Share a Link Copy URL https://explore.partquest.com/node/414864 Copy of LED Dimmer Circuit using 555 Timer - on Wed, 01/13/2021 - 19:51 anoorDesigner237496 × anoor Member for 3 years 2 months 0 designs 1 groups Title Description <p>This LED Dimmer Circuit uses a 555 Timer to control the PWM duty cycle of the current drive. Rather than apply proportional but continuous current to the LED for dimming, which can cause color shifts, modulating the duty cycle allows the LED to operate at its nominal current during the “ON” portion of the cycle. Because the frequency response of human vision is limited, using a PWM frequency of 250 Hz avoids the perception of flicker for the observer.</p> <p>The LED model has an internal monitor for the "perceived" light output (blue waveform), which is a low-pass filtered version of the instantaneous light output. The filter pole frequency is set to 15 Hz to represent the bandwidth of the human eye. The value of the dimmer setting (green waveform) is increased from 10% to 90% at time 100msec. The LED current pulses (red waveform) are shown before and after the duty-cycle transition.</p> <p>Part of this design is based on a dimmer schematic found on-line:</p> <p><a href="http://www.555-timer-circuits.com/led-dimmer.html">http://www.555-timer-circuits.com/led-dimmer.html</a></p> <p>That original circuit is actually incorrect, one of the diodes connected to pin 7 on the 555-Timer needs to be reversed. There was a comment from a reader who said he built the circuit as shown and it didn’t work. This is a good example of the value of simulating circuits before building hardware!</p> About text formats Tags 555 TimerLEDpotentiometer Select a tag from the list or create your own.Drag to re-order taxonomy terms. License - None - What's this? Design Titleby anoor × Embed Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/embed-design/402065"></iframe> Embed Live Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/node/402065"></iframe> Share a Link Copy URL https://explore.partquest.com/node/402065 Copy of LED Dimmer Circuit using 555 Timer - on Wed, 01/13/2021 - 19:51 anoorDesigner237496 × anoor Member for 3 years 2 months 0 designs 1 groups Title Description <p>This LED Dimmer Circuit uses a 555 Timer to control the PWM duty cycle of the current drive. Rather than apply proportional but continuous current to the LED for dimming, which can cause color shifts, modulating the duty cycle allows the LED to operate at its nominal current during the “ON” portion of the cycle. Because the frequency response of human vision is limited, using a PWM frequency of 250 Hz avoids the perception of flicker for the observer.</p> <p>The LED model has an internal monitor for the "perceived" light output (blue waveform), which is a low-pass filtered version of the instantaneous light output. The filter pole frequency is set to 15 Hz to represent the bandwidth of the human eye. The value of the dimmer setting (green waveform) is increased from 10% to 90% at time 100msec. The LED current pulses (red waveform) are shown before and after the duty-cycle transition.</p> <p>Part of this design is based on a dimmer schematic found on-line:</p> <p><a href="http://www.555-timer-circuits.com/led-dimmer.html">http://www.555-timer-circuits.com/led-dimmer.html</a></p> <p>That original circuit is actually incorrect, one of the diodes connected to pin 7 on the 555-Timer needs to be reversed. There was a comment from a reader who said he built the circuit as shown and it didn’t work. This is a good example of the value of simulating circuits before building hardware!</p> About text formats Tags 555 TimerLEDpotentiometer Select a tag from the list or create your own.Drag to re-order taxonomy terms. License - None - What's this? Design Titleby anoor × Embed Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/embed-design/402064"></iframe> Embed Live Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/node/402064"></iframe> Share a Link Copy URL https://explore.partquest.com/node/402064 Copy of LED Dimmer Circuit using 555 Timer - on Wed, 01/13/2021 - 19:51 anoorDesigner237496 × anoor Member for 3 years 2 months 0 designs 1 groups Title Description <p>This LED Dimmer Circuit uses a 555 Timer to control the PWM duty cycle of the current drive. Rather than apply proportional but continuous current to the LED for dimming, which can cause color shifts, modulating the duty cycle allows the LED to operate at its nominal current during the “ON” portion of the cycle. Because the frequency response of human vision is limited, using a PWM frequency of 250 Hz avoids the perception of flicker for the observer.</p> <p>The LED model has an internal monitor for the "perceived" light output (blue waveform), which is a low-pass filtered version of the instantaneous light output. The filter pole frequency is set to 15 Hz to represent the bandwidth of the human eye. The value of the dimmer setting (green waveform) is increased from 10% to 90% at time 100msec. The LED current pulses (red waveform) are shown before and after the duty-cycle transition.</p> <p>Part of this design is based on a dimmer schematic found on-line:</p> <p><a href="http://www.555-timer-circuits.com/led-dimmer.html">http://www.555-timer-circuits.com/led-dimmer.html</a></p> <p>That original circuit is actually incorrect, one of the diodes connected to pin 7 on the 555-Timer needs to be reversed. There was a comment from a reader who said he built the circuit as shown and it didn’t work. This is a good example of the value of simulating circuits before building hardware!</p> About text formats Tags 555 TimerLEDpotentiometer Select a tag from the list or create your own.Drag to re-order taxonomy terms. License - None - What's this? Design Titleby anoor × Embed Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/embed-design/402063"></iframe> Embed Live Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/node/402063"></iframe> Share a Link Copy URL https://explore.partquest.com/node/402063 Copy of LED Dimmer Circuit - on Thu, 01/07/2021 - 11:15 sami.jaberDesigner237221 × sami.jaber Member for 3 years 3 months 1 designs 1 groups Title Description <p>This LED Dimmer Circuit uses a 555 Timer to control the PWM duty cycle of the current drive. Rather than apply proportional but continuous current to the LED for dimming, which can cause color shifts, modulating the duty cycle allows the LED to operate at its nominal current during the “ON” portion of the cycle. Because the frequency response of human vision is limited, using a PWM frequency of 250 Hz avoids the perception of flicker for the observer.</p> <p>The LED model has an internal monitor for the "perceived" light output (blue waveform), which is a low-pass filtered version of the instantaneous light output. The filter pole frequency is set to 15 Hz to represent the bandwidth of the human eye. The value of the potentiometer setting (green waveform), which closely approximates the PWM duty-cycle, is increased from 10% to 90% at time 50msec. The LED current pulses (red waveform) are shown before and after that duty-cycle transition.</p> About text formats Tags 555 TimerLEDpotentiometer Select a tag from the list or create your own.Drag to re-order taxonomy terms. License - None - What's this? Design Titleby sami.jaber × Embed Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/embed-design/398853"></iframe> Embed Live Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/node/398853"></iframe> Share a Link Copy URL https://explore.partquest.com/node/398853 LED Dimmer Circuit - on Thu, 01/07/2021 - 17:56 tingwei0116Designer236121 × tingwei0116 Member for 3 years 5 months 8 designs 1 groups Title Description <p>This LED Dimmer Circuit uses a 555 Timer to control the PWM duty cycle of the current drive. Rather than apply proportional but continuous current to the LED for dimming, which can cause color shifts, modulating the duty cycle allows the LED to operate at its nominal current during the “ON” portion of the cycle. Because the frequency response of human vision is limited, using a PWM frequency of 250 Hz avoids the perception of flicker for the observer.</p> <p>The LED model has an internal monitor for the "perceived" light output (blue waveform), which is a low-pass filtered version of the instantaneous light output. The filter pole frequency is set to 15 Hz to represent the bandwidth of the human eye. The value of the potentiometer setting (green waveform), which closely approximates the PWM duty-cycle, is increased from 10% to 90% at time 50msec. The LED current pulses (red waveform) are shown before and after that duty-cycle transition.</p> About text formats Tags 555 TimerLEDpotentiometer Select a tag from the list or create your own.Drag to re-order taxonomy terms. License - None - What's this? Design Titleby tingwei0116 × Embed Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/embed-design/398836"></iframe> Embed Live Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/node/398836"></iframe> Share a Link Copy URL https://explore.partquest.com/node/398836 Copy of LED Dimmer Circuit using 555 Timer - on Wed, 12/30/2020 - 16:44 usman.qasim1994Designer237332 × usman.qasim1994 Member for 3 years 2 months 0 designs 1 groups Title Description <p>This LED Dimmer Circuit uses a 555 Timer to control the PWM duty cycle of the current drive. Rather than apply proportional but continuous current to the LED for dimming, which can cause color shifts, modulating the duty cycle allows the LED to operate at its nominal current during the “ON” portion of the cycle. Because the frequency response of human vision is limited, using a PWM frequency of 250 Hz avoids the perception of flicker for the observer.</p> <p>The LED model has an internal monitor for the "perceived" light output (blue waveform), which is a low-pass filtered version of the instantaneous light output. The filter pole frequency is set to 15 Hz to represent the bandwidth of the human eye. The value of the dimmer setting (green waveform) is increased from 10% to 90% at time 100msec. The LED current pulses (red waveform) are shown before and after the duty-cycle transition.</p> <p>Part of this design is based on a dimmer schematic found on-line:</p> <p><a href="http://www.555-timer-circuits.com/led-dimmer.html">http://www.555-timer-circuits.com/led-dimmer.html</a></p> <p>That original circuit is actually incorrect, one of the diodes connected to pin 7 on the 555-Timer needs to be reversed. There was a comment from a reader who said he built the circuit as shown and it didn’t work. This is a good example of the value of simulating circuits before building hardware!</p> About text formats Tags 555 TimerLEDpotentiometer Select a tag from the list or create your own.Drag to re-order taxonomy terms. License - None - What's this? Design Titleby usman.qasim1994 × Embed Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/embed-design/397033"></iframe> Embed Live Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/node/397033"></iframe> Share a Link Copy URL https://explore.partquest.com/node/397033 Pagination Previous page ‹‹ Page 2 Next page ››
Copy of Voltage divider circuit using potentiometer - on Mon, 03/01/2021 - 00:47 rayane2gadelha5Designer238057 × rayane2gadelha5 Member for 3 years 1 month 56 designs 2 groups Title Description <p>A simple example created to provide an example for a forum post on All About Circuits:</p> <p>http://forum.allaboutcircuits.com/threads/ltspice-problem-with-varying-parameters.117229/#post-945807</p> About text formats Tags potentiometerAAC Select a tag from the list or create your own.Drag to re-order taxonomy terms. License - None - What's this? Design Titleby rayane2gadelha5 × Embed Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/embed-design/414864"></iframe> Embed Live Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/node/414864"></iframe> Share a Link Copy URL https://explore.partquest.com/node/414864 Copy of LED Dimmer Circuit using 555 Timer - on Wed, 01/13/2021 - 19:51 anoorDesigner237496 × anoor Member for 3 years 2 months 0 designs 1 groups Title Description <p>This LED Dimmer Circuit uses a 555 Timer to control the PWM duty cycle of the current drive. Rather than apply proportional but continuous current to the LED for dimming, which can cause color shifts, modulating the duty cycle allows the LED to operate at its nominal current during the “ON” portion of the cycle. Because the frequency response of human vision is limited, using a PWM frequency of 250 Hz avoids the perception of flicker for the observer.</p> <p>The LED model has an internal monitor for the "perceived" light output (blue waveform), which is a low-pass filtered version of the instantaneous light output. The filter pole frequency is set to 15 Hz to represent the bandwidth of the human eye. The value of the dimmer setting (green waveform) is increased from 10% to 90% at time 100msec. The LED current pulses (red waveform) are shown before and after the duty-cycle transition.</p> <p>Part of this design is based on a dimmer schematic found on-line:</p> <p><a href="http://www.555-timer-circuits.com/led-dimmer.html">http://www.555-timer-circuits.com/led-dimmer.html</a></p> <p>That original circuit is actually incorrect, one of the diodes connected to pin 7 on the 555-Timer needs to be reversed. There was a comment from a reader who said he built the circuit as shown and it didn’t work. This is a good example of the value of simulating circuits before building hardware!</p> About text formats Tags 555 TimerLEDpotentiometer Select a tag from the list or create your own.Drag to re-order taxonomy terms. License - None - What's this? Design Titleby anoor × Embed Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/embed-design/402065"></iframe> Embed Live Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/node/402065"></iframe> Share a Link Copy URL https://explore.partquest.com/node/402065 Copy of LED Dimmer Circuit using 555 Timer - on Wed, 01/13/2021 - 19:51 anoorDesigner237496 × anoor Member for 3 years 2 months 0 designs 1 groups Title Description <p>This LED Dimmer Circuit uses a 555 Timer to control the PWM duty cycle of the current drive. Rather than apply proportional but continuous current to the LED for dimming, which can cause color shifts, modulating the duty cycle allows the LED to operate at its nominal current during the “ON” portion of the cycle. Because the frequency response of human vision is limited, using a PWM frequency of 250 Hz avoids the perception of flicker for the observer.</p> <p>The LED model has an internal monitor for the "perceived" light output (blue waveform), which is a low-pass filtered version of the instantaneous light output. The filter pole frequency is set to 15 Hz to represent the bandwidth of the human eye. The value of the dimmer setting (green waveform) is increased from 10% to 90% at time 100msec. The LED current pulses (red waveform) are shown before and after the duty-cycle transition.</p> <p>Part of this design is based on a dimmer schematic found on-line:</p> <p><a href="http://www.555-timer-circuits.com/led-dimmer.html">http://www.555-timer-circuits.com/led-dimmer.html</a></p> <p>That original circuit is actually incorrect, one of the diodes connected to pin 7 on the 555-Timer needs to be reversed. There was a comment from a reader who said he built the circuit as shown and it didn’t work. This is a good example of the value of simulating circuits before building hardware!</p> About text formats Tags 555 TimerLEDpotentiometer Select a tag from the list or create your own.Drag to re-order taxonomy terms. License - None - What's this? Design Titleby anoor × Embed Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/embed-design/402064"></iframe> Embed Live Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/node/402064"></iframe> Share a Link Copy URL https://explore.partquest.com/node/402064 Copy of LED Dimmer Circuit using 555 Timer - on Wed, 01/13/2021 - 19:51 anoorDesigner237496 × anoor Member for 3 years 2 months 0 designs 1 groups Title Description <p>This LED Dimmer Circuit uses a 555 Timer to control the PWM duty cycle of the current drive. Rather than apply proportional but continuous current to the LED for dimming, which can cause color shifts, modulating the duty cycle allows the LED to operate at its nominal current during the “ON” portion of the cycle. Because the frequency response of human vision is limited, using a PWM frequency of 250 Hz avoids the perception of flicker for the observer.</p> <p>The LED model has an internal monitor for the "perceived" light output (blue waveform), which is a low-pass filtered version of the instantaneous light output. The filter pole frequency is set to 15 Hz to represent the bandwidth of the human eye. The value of the dimmer setting (green waveform) is increased from 10% to 90% at time 100msec. The LED current pulses (red waveform) are shown before and after the duty-cycle transition.</p> <p>Part of this design is based on a dimmer schematic found on-line:</p> <p><a href="http://www.555-timer-circuits.com/led-dimmer.html">http://www.555-timer-circuits.com/led-dimmer.html</a></p> <p>That original circuit is actually incorrect, one of the diodes connected to pin 7 on the 555-Timer needs to be reversed. There was a comment from a reader who said he built the circuit as shown and it didn’t work. This is a good example of the value of simulating circuits before building hardware!</p> About text formats Tags 555 TimerLEDpotentiometer Select a tag from the list or create your own.Drag to re-order taxonomy terms. License - None - What's this? Design Titleby anoor × Embed Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/embed-design/402063"></iframe> Embed Live Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/node/402063"></iframe> Share a Link Copy URL https://explore.partquest.com/node/402063 Copy of LED Dimmer Circuit - on Thu, 01/07/2021 - 11:15 sami.jaberDesigner237221 × sami.jaber Member for 3 years 3 months 1 designs 1 groups Title Description <p>This LED Dimmer Circuit uses a 555 Timer to control the PWM duty cycle of the current drive. Rather than apply proportional but continuous current to the LED for dimming, which can cause color shifts, modulating the duty cycle allows the LED to operate at its nominal current during the “ON” portion of the cycle. Because the frequency response of human vision is limited, using a PWM frequency of 250 Hz avoids the perception of flicker for the observer.</p> <p>The LED model has an internal monitor for the "perceived" light output (blue waveform), which is a low-pass filtered version of the instantaneous light output. The filter pole frequency is set to 15 Hz to represent the bandwidth of the human eye. The value of the potentiometer setting (green waveform), which closely approximates the PWM duty-cycle, is increased from 10% to 90% at time 50msec. The LED current pulses (red waveform) are shown before and after that duty-cycle transition.</p> About text formats Tags 555 TimerLEDpotentiometer Select a tag from the list or create your own.Drag to re-order taxonomy terms. License - None - What's this? Design Titleby sami.jaber × Embed Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/embed-design/398853"></iframe> Embed Live Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/node/398853"></iframe> Share a Link Copy URL https://explore.partquest.com/node/398853 LED Dimmer Circuit - on Thu, 01/07/2021 - 17:56 tingwei0116Designer236121 × tingwei0116 Member for 3 years 5 months 8 designs 1 groups Title Description <p>This LED Dimmer Circuit uses a 555 Timer to control the PWM duty cycle of the current drive. Rather than apply proportional but continuous current to the LED for dimming, which can cause color shifts, modulating the duty cycle allows the LED to operate at its nominal current during the “ON” portion of the cycle. Because the frequency response of human vision is limited, using a PWM frequency of 250 Hz avoids the perception of flicker for the observer.</p> <p>The LED model has an internal monitor for the "perceived" light output (blue waveform), which is a low-pass filtered version of the instantaneous light output. The filter pole frequency is set to 15 Hz to represent the bandwidth of the human eye. The value of the potentiometer setting (green waveform), which closely approximates the PWM duty-cycle, is increased from 10% to 90% at time 50msec. The LED current pulses (red waveform) are shown before and after that duty-cycle transition.</p> About text formats Tags 555 TimerLEDpotentiometer Select a tag from the list or create your own.Drag to re-order taxonomy terms. License - None - What's this? Design Titleby tingwei0116 × Embed Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/embed-design/398836"></iframe> Embed Live Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/node/398836"></iframe> Share a Link Copy URL https://explore.partquest.com/node/398836 Copy of LED Dimmer Circuit using 555 Timer - on Wed, 12/30/2020 - 16:44 usman.qasim1994Designer237332 × usman.qasim1994 Member for 3 years 2 months 0 designs 1 groups Title Description <p>This LED Dimmer Circuit uses a 555 Timer to control the PWM duty cycle of the current drive. Rather than apply proportional but continuous current to the LED for dimming, which can cause color shifts, modulating the duty cycle allows the LED to operate at its nominal current during the “ON” portion of the cycle. Because the frequency response of human vision is limited, using a PWM frequency of 250 Hz avoids the perception of flicker for the observer.</p> <p>The LED model has an internal monitor for the "perceived" light output (blue waveform), which is a low-pass filtered version of the instantaneous light output. The filter pole frequency is set to 15 Hz to represent the bandwidth of the human eye. The value of the dimmer setting (green waveform) is increased from 10% to 90% at time 100msec. The LED current pulses (red waveform) are shown before and after the duty-cycle transition.</p> <p>Part of this design is based on a dimmer schematic found on-line:</p> <p><a href="http://www.555-timer-circuits.com/led-dimmer.html">http://www.555-timer-circuits.com/led-dimmer.html</a></p> <p>That original circuit is actually incorrect, one of the diodes connected to pin 7 on the 555-Timer needs to be reversed. There was a comment from a reader who said he built the circuit as shown and it didn’t work. This is a good example of the value of simulating circuits before building hardware!</p> About text formats Tags 555 TimerLEDpotentiometer Select a tag from the list or create your own.Drag to re-order taxonomy terms. License - None - What's this? Design Titleby usman.qasim1994 × Embed Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/embed-design/397033"></iframe> Embed Live Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/node/397033"></iframe> Share a Link Copy URL https://explore.partquest.com/node/397033 Pagination Previous page ‹‹ Page 2 Next page ››
Copy of LED Dimmer Circuit using 555 Timer - on Wed, 01/13/2021 - 19:51 anoorDesigner237496 × anoor Member for 3 years 2 months 0 designs 1 groups Title Description <p>This LED Dimmer Circuit uses a 555 Timer to control the PWM duty cycle of the current drive. Rather than apply proportional but continuous current to the LED for dimming, which can cause color shifts, modulating the duty cycle allows the LED to operate at its nominal current during the “ON” portion of the cycle. Because the frequency response of human vision is limited, using a PWM frequency of 250 Hz avoids the perception of flicker for the observer.</p> <p>The LED model has an internal monitor for the "perceived" light output (blue waveform), which is a low-pass filtered version of the instantaneous light output. The filter pole frequency is set to 15 Hz to represent the bandwidth of the human eye. The value of the dimmer setting (green waveform) is increased from 10% to 90% at time 100msec. The LED current pulses (red waveform) are shown before and after the duty-cycle transition.</p> <p>Part of this design is based on a dimmer schematic found on-line:</p> <p><a href="http://www.555-timer-circuits.com/led-dimmer.html">http://www.555-timer-circuits.com/led-dimmer.html</a></p> <p>That original circuit is actually incorrect, one of the diodes connected to pin 7 on the 555-Timer needs to be reversed. There was a comment from a reader who said he built the circuit as shown and it didn’t work. This is a good example of the value of simulating circuits before building hardware!</p> About text formats Tags 555 TimerLEDpotentiometer Select a tag from the list or create your own.Drag to re-order taxonomy terms. License - None - What's this? Design Titleby anoor × Embed Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/embed-design/402065"></iframe> Embed Live Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/node/402065"></iframe> Share a Link Copy URL https://explore.partquest.com/node/402065 Copy of LED Dimmer Circuit using 555 Timer - on Wed, 01/13/2021 - 19:51 anoorDesigner237496 × anoor Member for 3 years 2 months 0 designs 1 groups Title Description <p>This LED Dimmer Circuit uses a 555 Timer to control the PWM duty cycle of the current drive. Rather than apply proportional but continuous current to the LED for dimming, which can cause color shifts, modulating the duty cycle allows the LED to operate at its nominal current during the “ON” portion of the cycle. Because the frequency response of human vision is limited, using a PWM frequency of 250 Hz avoids the perception of flicker for the observer.</p> <p>The LED model has an internal monitor for the "perceived" light output (blue waveform), which is a low-pass filtered version of the instantaneous light output. The filter pole frequency is set to 15 Hz to represent the bandwidth of the human eye. The value of the dimmer setting (green waveform) is increased from 10% to 90% at time 100msec. The LED current pulses (red waveform) are shown before and after the duty-cycle transition.</p> <p>Part of this design is based on a dimmer schematic found on-line:</p> <p><a href="http://www.555-timer-circuits.com/led-dimmer.html">http://www.555-timer-circuits.com/led-dimmer.html</a></p> <p>That original circuit is actually incorrect, one of the diodes connected to pin 7 on the 555-Timer needs to be reversed. There was a comment from a reader who said he built the circuit as shown and it didn’t work. This is a good example of the value of simulating circuits before building hardware!</p> About text formats Tags 555 TimerLEDpotentiometer Select a tag from the list or create your own.Drag to re-order taxonomy terms. License - None - What's this? Design Titleby anoor × Embed Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/embed-design/402064"></iframe> Embed Live Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/node/402064"></iframe> Share a Link Copy URL https://explore.partquest.com/node/402064 Copy of LED Dimmer Circuit using 555 Timer - on Wed, 01/13/2021 - 19:51 anoorDesigner237496 × anoor Member for 3 years 2 months 0 designs 1 groups Title Description <p>This LED Dimmer Circuit uses a 555 Timer to control the PWM duty cycle of the current drive. Rather than apply proportional but continuous current to the LED for dimming, which can cause color shifts, modulating the duty cycle allows the LED to operate at its nominal current during the “ON” portion of the cycle. Because the frequency response of human vision is limited, using a PWM frequency of 250 Hz avoids the perception of flicker for the observer.</p> <p>The LED model has an internal monitor for the "perceived" light output (blue waveform), which is a low-pass filtered version of the instantaneous light output. The filter pole frequency is set to 15 Hz to represent the bandwidth of the human eye. The value of the dimmer setting (green waveform) is increased from 10% to 90% at time 100msec. The LED current pulses (red waveform) are shown before and after the duty-cycle transition.</p> <p>Part of this design is based on a dimmer schematic found on-line:</p> <p><a href="http://www.555-timer-circuits.com/led-dimmer.html">http://www.555-timer-circuits.com/led-dimmer.html</a></p> <p>That original circuit is actually incorrect, one of the diodes connected to pin 7 on the 555-Timer needs to be reversed. There was a comment from a reader who said he built the circuit as shown and it didn’t work. This is a good example of the value of simulating circuits before building hardware!</p> About text formats Tags 555 TimerLEDpotentiometer Select a tag from the list or create your own.Drag to re-order taxonomy terms. License - None - What's this? Design Titleby anoor × Embed Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/embed-design/402063"></iframe> Embed Live Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/node/402063"></iframe> Share a Link Copy URL https://explore.partquest.com/node/402063 Copy of LED Dimmer Circuit - on Thu, 01/07/2021 - 11:15 sami.jaberDesigner237221 × sami.jaber Member for 3 years 3 months 1 designs 1 groups Title Description <p>This LED Dimmer Circuit uses a 555 Timer to control the PWM duty cycle of the current drive. Rather than apply proportional but continuous current to the LED for dimming, which can cause color shifts, modulating the duty cycle allows the LED to operate at its nominal current during the “ON” portion of the cycle. Because the frequency response of human vision is limited, using a PWM frequency of 250 Hz avoids the perception of flicker for the observer.</p> <p>The LED model has an internal monitor for the "perceived" light output (blue waveform), which is a low-pass filtered version of the instantaneous light output. The filter pole frequency is set to 15 Hz to represent the bandwidth of the human eye. The value of the potentiometer setting (green waveform), which closely approximates the PWM duty-cycle, is increased from 10% to 90% at time 50msec. The LED current pulses (red waveform) are shown before and after that duty-cycle transition.</p> About text formats Tags 555 TimerLEDpotentiometer Select a tag from the list or create your own.Drag to re-order taxonomy terms. License - None - What's this? Design Titleby sami.jaber × Embed Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/embed-design/398853"></iframe> Embed Live Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/node/398853"></iframe> Share a Link Copy URL https://explore.partquest.com/node/398853 LED Dimmer Circuit - on Thu, 01/07/2021 - 17:56 tingwei0116Designer236121 × tingwei0116 Member for 3 years 5 months 8 designs 1 groups Title Description <p>This LED Dimmer Circuit uses a 555 Timer to control the PWM duty cycle of the current drive. Rather than apply proportional but continuous current to the LED for dimming, which can cause color shifts, modulating the duty cycle allows the LED to operate at its nominal current during the “ON” portion of the cycle. Because the frequency response of human vision is limited, using a PWM frequency of 250 Hz avoids the perception of flicker for the observer.</p> <p>The LED model has an internal monitor for the "perceived" light output (blue waveform), which is a low-pass filtered version of the instantaneous light output. The filter pole frequency is set to 15 Hz to represent the bandwidth of the human eye. The value of the potentiometer setting (green waveform), which closely approximates the PWM duty-cycle, is increased from 10% to 90% at time 50msec. The LED current pulses (red waveform) are shown before and after that duty-cycle transition.</p> About text formats Tags 555 TimerLEDpotentiometer Select a tag from the list or create your own.Drag to re-order taxonomy terms. License - None - What's this? Design Titleby tingwei0116 × Embed Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/embed-design/398836"></iframe> Embed Live Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/node/398836"></iframe> Share a Link Copy URL https://explore.partquest.com/node/398836 Copy of LED Dimmer Circuit using 555 Timer - on Wed, 12/30/2020 - 16:44 usman.qasim1994Designer237332 × usman.qasim1994 Member for 3 years 2 months 0 designs 1 groups Title Description <p>This LED Dimmer Circuit uses a 555 Timer to control the PWM duty cycle of the current drive. Rather than apply proportional but continuous current to the LED for dimming, which can cause color shifts, modulating the duty cycle allows the LED to operate at its nominal current during the “ON” portion of the cycle. Because the frequency response of human vision is limited, using a PWM frequency of 250 Hz avoids the perception of flicker for the observer.</p> <p>The LED model has an internal monitor for the "perceived" light output (blue waveform), which is a low-pass filtered version of the instantaneous light output. The filter pole frequency is set to 15 Hz to represent the bandwidth of the human eye. The value of the dimmer setting (green waveform) is increased from 10% to 90% at time 100msec. The LED current pulses (red waveform) are shown before and after the duty-cycle transition.</p> <p>Part of this design is based on a dimmer schematic found on-line:</p> <p><a href="http://www.555-timer-circuits.com/led-dimmer.html">http://www.555-timer-circuits.com/led-dimmer.html</a></p> <p>That original circuit is actually incorrect, one of the diodes connected to pin 7 on the 555-Timer needs to be reversed. There was a comment from a reader who said he built the circuit as shown and it didn’t work. This is a good example of the value of simulating circuits before building hardware!</p> About text formats Tags 555 TimerLEDpotentiometer Select a tag from the list or create your own.Drag to re-order taxonomy terms. License - None - What's this? Design Titleby usman.qasim1994 × Embed Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/embed-design/397033"></iframe> Embed Live Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/node/397033"></iframe> Share a Link Copy URL https://explore.partquest.com/node/397033 Pagination Previous page ‹‹ Page 2 Next page ››
Copy of LED Dimmer Circuit using 555 Timer - on Wed, 01/13/2021 - 19:51 anoorDesigner237496 × anoor Member for 3 years 2 months 0 designs 1 groups Title Description <p>This LED Dimmer Circuit uses a 555 Timer to control the PWM duty cycle of the current drive. Rather than apply proportional but continuous current to the LED for dimming, which can cause color shifts, modulating the duty cycle allows the LED to operate at its nominal current during the “ON” portion of the cycle. Because the frequency response of human vision is limited, using a PWM frequency of 250 Hz avoids the perception of flicker for the observer.</p> <p>The LED model has an internal monitor for the "perceived" light output (blue waveform), which is a low-pass filtered version of the instantaneous light output. The filter pole frequency is set to 15 Hz to represent the bandwidth of the human eye. The value of the dimmer setting (green waveform) is increased from 10% to 90% at time 100msec. The LED current pulses (red waveform) are shown before and after the duty-cycle transition.</p> <p>Part of this design is based on a dimmer schematic found on-line:</p> <p><a href="http://www.555-timer-circuits.com/led-dimmer.html">http://www.555-timer-circuits.com/led-dimmer.html</a></p> <p>That original circuit is actually incorrect, one of the diodes connected to pin 7 on the 555-Timer needs to be reversed. There was a comment from a reader who said he built the circuit as shown and it didn’t work. This is a good example of the value of simulating circuits before building hardware!</p> About text formats Tags 555 TimerLEDpotentiometer Select a tag from the list or create your own.Drag to re-order taxonomy terms. License - None - What's this? Design Titleby anoor × Embed Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/embed-design/402064"></iframe> Embed Live Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/node/402064"></iframe> Share a Link Copy URL https://explore.partquest.com/node/402064 Copy of LED Dimmer Circuit using 555 Timer - on Wed, 01/13/2021 - 19:51 anoorDesigner237496 × anoor Member for 3 years 2 months 0 designs 1 groups Title Description <p>This LED Dimmer Circuit uses a 555 Timer to control the PWM duty cycle of the current drive. Rather than apply proportional but continuous current to the LED for dimming, which can cause color shifts, modulating the duty cycle allows the LED to operate at its nominal current during the “ON” portion of the cycle. Because the frequency response of human vision is limited, using a PWM frequency of 250 Hz avoids the perception of flicker for the observer.</p> <p>The LED model has an internal monitor for the "perceived" light output (blue waveform), which is a low-pass filtered version of the instantaneous light output. The filter pole frequency is set to 15 Hz to represent the bandwidth of the human eye. The value of the dimmer setting (green waveform) is increased from 10% to 90% at time 100msec. The LED current pulses (red waveform) are shown before and after the duty-cycle transition.</p> <p>Part of this design is based on a dimmer schematic found on-line:</p> <p><a href="http://www.555-timer-circuits.com/led-dimmer.html">http://www.555-timer-circuits.com/led-dimmer.html</a></p> <p>That original circuit is actually incorrect, one of the diodes connected to pin 7 on the 555-Timer needs to be reversed. There was a comment from a reader who said he built the circuit as shown and it didn’t work. This is a good example of the value of simulating circuits before building hardware!</p> About text formats Tags 555 TimerLEDpotentiometer Select a tag from the list or create your own.Drag to re-order taxonomy terms. License - None - What's this? Design Titleby anoor × Embed Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/embed-design/402063"></iframe> Embed Live Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/node/402063"></iframe> Share a Link Copy URL https://explore.partquest.com/node/402063 Copy of LED Dimmer Circuit - on Thu, 01/07/2021 - 11:15 sami.jaberDesigner237221 × sami.jaber Member for 3 years 3 months 1 designs 1 groups Title Description <p>This LED Dimmer Circuit uses a 555 Timer to control the PWM duty cycle of the current drive. Rather than apply proportional but continuous current to the LED for dimming, which can cause color shifts, modulating the duty cycle allows the LED to operate at its nominal current during the “ON” portion of the cycle. Because the frequency response of human vision is limited, using a PWM frequency of 250 Hz avoids the perception of flicker for the observer.</p> <p>The LED model has an internal monitor for the "perceived" light output (blue waveform), which is a low-pass filtered version of the instantaneous light output. The filter pole frequency is set to 15 Hz to represent the bandwidth of the human eye. The value of the potentiometer setting (green waveform), which closely approximates the PWM duty-cycle, is increased from 10% to 90% at time 50msec. The LED current pulses (red waveform) are shown before and after that duty-cycle transition.</p> About text formats Tags 555 TimerLEDpotentiometer Select a tag from the list or create your own.Drag to re-order taxonomy terms. License - None - What's this? Design Titleby sami.jaber × Embed Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/embed-design/398853"></iframe> Embed Live Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/node/398853"></iframe> Share a Link Copy URL https://explore.partquest.com/node/398853 LED Dimmer Circuit - on Thu, 01/07/2021 - 17:56 tingwei0116Designer236121 × tingwei0116 Member for 3 years 5 months 8 designs 1 groups Title Description <p>This LED Dimmer Circuit uses a 555 Timer to control the PWM duty cycle of the current drive. Rather than apply proportional but continuous current to the LED for dimming, which can cause color shifts, modulating the duty cycle allows the LED to operate at its nominal current during the “ON” portion of the cycle. Because the frequency response of human vision is limited, using a PWM frequency of 250 Hz avoids the perception of flicker for the observer.</p> <p>The LED model has an internal monitor for the "perceived" light output (blue waveform), which is a low-pass filtered version of the instantaneous light output. The filter pole frequency is set to 15 Hz to represent the bandwidth of the human eye. The value of the potentiometer setting (green waveform), which closely approximates the PWM duty-cycle, is increased from 10% to 90% at time 50msec. The LED current pulses (red waveform) are shown before and after that duty-cycle transition.</p> About text formats Tags 555 TimerLEDpotentiometer Select a tag from the list or create your own.Drag to re-order taxonomy terms. License - None - What's this? Design Titleby tingwei0116 × Embed Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/embed-design/398836"></iframe> Embed Live Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/node/398836"></iframe> Share a Link Copy URL https://explore.partquest.com/node/398836 Copy of LED Dimmer Circuit using 555 Timer - on Wed, 12/30/2020 - 16:44 usman.qasim1994Designer237332 × usman.qasim1994 Member for 3 years 2 months 0 designs 1 groups Title Description <p>This LED Dimmer Circuit uses a 555 Timer to control the PWM duty cycle of the current drive. Rather than apply proportional but continuous current to the LED for dimming, which can cause color shifts, modulating the duty cycle allows the LED to operate at its nominal current during the “ON” portion of the cycle. Because the frequency response of human vision is limited, using a PWM frequency of 250 Hz avoids the perception of flicker for the observer.</p> <p>The LED model has an internal monitor for the "perceived" light output (blue waveform), which is a low-pass filtered version of the instantaneous light output. The filter pole frequency is set to 15 Hz to represent the bandwidth of the human eye. The value of the dimmer setting (green waveform) is increased from 10% to 90% at time 100msec. The LED current pulses (red waveform) are shown before and after the duty-cycle transition.</p> <p>Part of this design is based on a dimmer schematic found on-line:</p> <p><a href="http://www.555-timer-circuits.com/led-dimmer.html">http://www.555-timer-circuits.com/led-dimmer.html</a></p> <p>That original circuit is actually incorrect, one of the diodes connected to pin 7 on the 555-Timer needs to be reversed. There was a comment from a reader who said he built the circuit as shown and it didn’t work. This is a good example of the value of simulating circuits before building hardware!</p> About text formats Tags 555 TimerLEDpotentiometer Select a tag from the list or create your own.Drag to re-order taxonomy terms. License - None - What's this? Design Titleby usman.qasim1994 × Embed Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/embed-design/397033"></iframe> Embed Live Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/node/397033"></iframe> Share a Link Copy URL https://explore.partquest.com/node/397033 Pagination Previous page ‹‹ Page 2 Next page ››
Copy of LED Dimmer Circuit using 555 Timer - on Wed, 01/13/2021 - 19:51 anoorDesigner237496 × anoor Member for 3 years 2 months 0 designs 1 groups Title Description <p>This LED Dimmer Circuit uses a 555 Timer to control the PWM duty cycle of the current drive. Rather than apply proportional but continuous current to the LED for dimming, which can cause color shifts, modulating the duty cycle allows the LED to operate at its nominal current during the “ON” portion of the cycle. Because the frequency response of human vision is limited, using a PWM frequency of 250 Hz avoids the perception of flicker for the observer.</p> <p>The LED model has an internal monitor for the "perceived" light output (blue waveform), which is a low-pass filtered version of the instantaneous light output. The filter pole frequency is set to 15 Hz to represent the bandwidth of the human eye. The value of the dimmer setting (green waveform) is increased from 10% to 90% at time 100msec. The LED current pulses (red waveform) are shown before and after the duty-cycle transition.</p> <p>Part of this design is based on a dimmer schematic found on-line:</p> <p><a href="http://www.555-timer-circuits.com/led-dimmer.html">http://www.555-timer-circuits.com/led-dimmer.html</a></p> <p>That original circuit is actually incorrect, one of the diodes connected to pin 7 on the 555-Timer needs to be reversed. There was a comment from a reader who said he built the circuit as shown and it didn’t work. This is a good example of the value of simulating circuits before building hardware!</p> About text formats Tags 555 TimerLEDpotentiometer Select a tag from the list or create your own.Drag to re-order taxonomy terms. License - None - What's this? Design Titleby anoor × Embed Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/embed-design/402063"></iframe> Embed Live Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/node/402063"></iframe> Share a Link Copy URL https://explore.partquest.com/node/402063 Copy of LED Dimmer Circuit - on Thu, 01/07/2021 - 11:15 sami.jaberDesigner237221 × sami.jaber Member for 3 years 3 months 1 designs 1 groups Title Description <p>This LED Dimmer Circuit uses a 555 Timer to control the PWM duty cycle of the current drive. Rather than apply proportional but continuous current to the LED for dimming, which can cause color shifts, modulating the duty cycle allows the LED to operate at its nominal current during the “ON” portion of the cycle. Because the frequency response of human vision is limited, using a PWM frequency of 250 Hz avoids the perception of flicker for the observer.</p> <p>The LED model has an internal monitor for the "perceived" light output (blue waveform), which is a low-pass filtered version of the instantaneous light output. The filter pole frequency is set to 15 Hz to represent the bandwidth of the human eye. The value of the potentiometer setting (green waveform), which closely approximates the PWM duty-cycle, is increased from 10% to 90% at time 50msec. The LED current pulses (red waveform) are shown before and after that duty-cycle transition.</p> About text formats Tags 555 TimerLEDpotentiometer Select a tag from the list or create your own.Drag to re-order taxonomy terms. License - None - What's this? Design Titleby sami.jaber × Embed Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/embed-design/398853"></iframe> Embed Live Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/node/398853"></iframe> Share a Link Copy URL https://explore.partquest.com/node/398853 LED Dimmer Circuit - on Thu, 01/07/2021 - 17:56 tingwei0116Designer236121 × tingwei0116 Member for 3 years 5 months 8 designs 1 groups Title Description <p>This LED Dimmer Circuit uses a 555 Timer to control the PWM duty cycle of the current drive. Rather than apply proportional but continuous current to the LED for dimming, which can cause color shifts, modulating the duty cycle allows the LED to operate at its nominal current during the “ON” portion of the cycle. Because the frequency response of human vision is limited, using a PWM frequency of 250 Hz avoids the perception of flicker for the observer.</p> <p>The LED model has an internal monitor for the "perceived" light output (blue waveform), which is a low-pass filtered version of the instantaneous light output. The filter pole frequency is set to 15 Hz to represent the bandwidth of the human eye. The value of the potentiometer setting (green waveform), which closely approximates the PWM duty-cycle, is increased from 10% to 90% at time 50msec. The LED current pulses (red waveform) are shown before and after that duty-cycle transition.</p> About text formats Tags 555 TimerLEDpotentiometer Select a tag from the list or create your own.Drag to re-order taxonomy terms. License - None - What's this? Design Titleby tingwei0116 × Embed Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/embed-design/398836"></iframe> Embed Live Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/node/398836"></iframe> Share a Link Copy URL https://explore.partquest.com/node/398836 Copy of LED Dimmer Circuit using 555 Timer - on Wed, 12/30/2020 - 16:44 usman.qasim1994Designer237332 × usman.qasim1994 Member for 3 years 2 months 0 designs 1 groups Title Description <p>This LED Dimmer Circuit uses a 555 Timer to control the PWM duty cycle of the current drive. Rather than apply proportional but continuous current to the LED for dimming, which can cause color shifts, modulating the duty cycle allows the LED to operate at its nominal current during the “ON” portion of the cycle. Because the frequency response of human vision is limited, using a PWM frequency of 250 Hz avoids the perception of flicker for the observer.</p> <p>The LED model has an internal monitor for the "perceived" light output (blue waveform), which is a low-pass filtered version of the instantaneous light output. The filter pole frequency is set to 15 Hz to represent the bandwidth of the human eye. The value of the dimmer setting (green waveform) is increased from 10% to 90% at time 100msec. The LED current pulses (red waveform) are shown before and after the duty-cycle transition.</p> <p>Part of this design is based on a dimmer schematic found on-line:</p> <p><a href="http://www.555-timer-circuits.com/led-dimmer.html">http://www.555-timer-circuits.com/led-dimmer.html</a></p> <p>That original circuit is actually incorrect, one of the diodes connected to pin 7 on the 555-Timer needs to be reversed. There was a comment from a reader who said he built the circuit as shown and it didn’t work. This is a good example of the value of simulating circuits before building hardware!</p> About text formats Tags 555 TimerLEDpotentiometer Select a tag from the list or create your own.Drag to re-order taxonomy terms. License - None - What's this? Design Titleby usman.qasim1994 × Embed Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/embed-design/397033"></iframe> Embed Live Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/node/397033"></iframe> Share a Link Copy URL https://explore.partquest.com/node/397033 Pagination Previous page ‹‹ Page 2 Next page ››
Copy of LED Dimmer Circuit - on Thu, 01/07/2021 - 11:15 sami.jaberDesigner237221 × sami.jaber Member for 3 years 3 months 1 designs 1 groups Title Description <p>This LED Dimmer Circuit uses a 555 Timer to control the PWM duty cycle of the current drive. Rather than apply proportional but continuous current to the LED for dimming, which can cause color shifts, modulating the duty cycle allows the LED to operate at its nominal current during the “ON” portion of the cycle. Because the frequency response of human vision is limited, using a PWM frequency of 250 Hz avoids the perception of flicker for the observer.</p> <p>The LED model has an internal monitor for the "perceived" light output (blue waveform), which is a low-pass filtered version of the instantaneous light output. The filter pole frequency is set to 15 Hz to represent the bandwidth of the human eye. The value of the potentiometer setting (green waveform), which closely approximates the PWM duty-cycle, is increased from 10% to 90% at time 50msec. The LED current pulses (red waveform) are shown before and after that duty-cycle transition.</p> About text formats Tags 555 TimerLEDpotentiometer Select a tag from the list or create your own.Drag to re-order taxonomy terms. License - None - What's this? Design Titleby sami.jaber × Embed Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/embed-design/398853"></iframe> Embed Live Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/node/398853"></iframe> Share a Link Copy URL https://explore.partquest.com/node/398853 LED Dimmer Circuit - on Thu, 01/07/2021 - 17:56 tingwei0116Designer236121 × tingwei0116 Member for 3 years 5 months 8 designs 1 groups Title Description <p>This LED Dimmer Circuit uses a 555 Timer to control the PWM duty cycle of the current drive. Rather than apply proportional but continuous current to the LED for dimming, which can cause color shifts, modulating the duty cycle allows the LED to operate at its nominal current during the “ON” portion of the cycle. Because the frequency response of human vision is limited, using a PWM frequency of 250 Hz avoids the perception of flicker for the observer.</p> <p>The LED model has an internal monitor for the "perceived" light output (blue waveform), which is a low-pass filtered version of the instantaneous light output. The filter pole frequency is set to 15 Hz to represent the bandwidth of the human eye. The value of the potentiometer setting (green waveform), which closely approximates the PWM duty-cycle, is increased from 10% to 90% at time 50msec. The LED current pulses (red waveform) are shown before and after that duty-cycle transition.</p> About text formats Tags 555 TimerLEDpotentiometer Select a tag from the list or create your own.Drag to re-order taxonomy terms. License - None - What's this? Design Titleby tingwei0116 × Embed Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/embed-design/398836"></iframe> Embed Live Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/node/398836"></iframe> Share a Link Copy URL https://explore.partquest.com/node/398836 Copy of LED Dimmer Circuit using 555 Timer - on Wed, 12/30/2020 - 16:44 usman.qasim1994Designer237332 × usman.qasim1994 Member for 3 years 2 months 0 designs 1 groups Title Description <p>This LED Dimmer Circuit uses a 555 Timer to control the PWM duty cycle of the current drive. Rather than apply proportional but continuous current to the LED for dimming, which can cause color shifts, modulating the duty cycle allows the LED to operate at its nominal current during the “ON” portion of the cycle. Because the frequency response of human vision is limited, using a PWM frequency of 250 Hz avoids the perception of flicker for the observer.</p> <p>The LED model has an internal monitor for the "perceived" light output (blue waveform), which is a low-pass filtered version of the instantaneous light output. The filter pole frequency is set to 15 Hz to represent the bandwidth of the human eye. The value of the dimmer setting (green waveform) is increased from 10% to 90% at time 100msec. The LED current pulses (red waveform) are shown before and after the duty-cycle transition.</p> <p>Part of this design is based on a dimmer schematic found on-line:</p> <p><a href="http://www.555-timer-circuits.com/led-dimmer.html">http://www.555-timer-circuits.com/led-dimmer.html</a></p> <p>That original circuit is actually incorrect, one of the diodes connected to pin 7 on the 555-Timer needs to be reversed. There was a comment from a reader who said he built the circuit as shown and it didn’t work. This is a good example of the value of simulating circuits before building hardware!</p> About text formats Tags 555 TimerLEDpotentiometer Select a tag from the list or create your own.Drag to re-order taxonomy terms. License - None - What's this? Design Titleby usman.qasim1994 × Embed Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/embed-design/397033"></iframe> Embed Live Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/node/397033"></iframe> Share a Link Copy URL https://explore.partquest.com/node/397033 Pagination Previous page ‹‹ Page 2 Next page ››
LED Dimmer Circuit - on Thu, 01/07/2021 - 17:56 tingwei0116Designer236121 × tingwei0116 Member for 3 years 5 months 8 designs 1 groups Title Description <p>This LED Dimmer Circuit uses a 555 Timer to control the PWM duty cycle of the current drive. Rather than apply proportional but continuous current to the LED for dimming, which can cause color shifts, modulating the duty cycle allows the LED to operate at its nominal current during the “ON” portion of the cycle. Because the frequency response of human vision is limited, using a PWM frequency of 250 Hz avoids the perception of flicker for the observer.</p> <p>The LED model has an internal monitor for the "perceived" light output (blue waveform), which is a low-pass filtered version of the instantaneous light output. The filter pole frequency is set to 15 Hz to represent the bandwidth of the human eye. The value of the potentiometer setting (green waveform), which closely approximates the PWM duty-cycle, is increased from 10% to 90% at time 50msec. The LED current pulses (red waveform) are shown before and after that duty-cycle transition.</p> About text formats Tags 555 TimerLEDpotentiometer Select a tag from the list or create your own.Drag to re-order taxonomy terms. License - None - What's this? Design Titleby tingwei0116 × Embed Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/embed-design/398836"></iframe> Embed Live Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/node/398836"></iframe> Share a Link Copy URL https://explore.partquest.com/node/398836 Copy of LED Dimmer Circuit using 555 Timer - on Wed, 12/30/2020 - 16:44 usman.qasim1994Designer237332 × usman.qasim1994 Member for 3 years 2 months 0 designs 1 groups Title Description <p>This LED Dimmer Circuit uses a 555 Timer to control the PWM duty cycle of the current drive. Rather than apply proportional but continuous current to the LED for dimming, which can cause color shifts, modulating the duty cycle allows the LED to operate at its nominal current during the “ON” portion of the cycle. Because the frequency response of human vision is limited, using a PWM frequency of 250 Hz avoids the perception of flicker for the observer.</p> <p>The LED model has an internal monitor for the "perceived" light output (blue waveform), which is a low-pass filtered version of the instantaneous light output. The filter pole frequency is set to 15 Hz to represent the bandwidth of the human eye. The value of the dimmer setting (green waveform) is increased from 10% to 90% at time 100msec. The LED current pulses (red waveform) are shown before and after the duty-cycle transition.</p> <p>Part of this design is based on a dimmer schematic found on-line:</p> <p><a href="http://www.555-timer-circuits.com/led-dimmer.html">http://www.555-timer-circuits.com/led-dimmer.html</a></p> <p>That original circuit is actually incorrect, one of the diodes connected to pin 7 on the 555-Timer needs to be reversed. There was a comment from a reader who said he built the circuit as shown and it didn’t work. This is a good example of the value of simulating circuits before building hardware!</p> About text formats Tags 555 TimerLEDpotentiometer Select a tag from the list or create your own.Drag to re-order taxonomy terms. License - None - What's this? Design Titleby usman.qasim1994 × Embed Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/embed-design/397033"></iframe> Embed Live Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/node/397033"></iframe> Share a Link Copy URL https://explore.partquest.com/node/397033 Pagination Previous page ‹‹ Page 2 Next page ››
Copy of LED Dimmer Circuit using 555 Timer - on Wed, 12/30/2020 - 16:44 usman.qasim1994Designer237332 × usman.qasim1994 Member for 3 years 2 months 0 designs 1 groups Title Description <p>This LED Dimmer Circuit uses a 555 Timer to control the PWM duty cycle of the current drive. Rather than apply proportional but continuous current to the LED for dimming, which can cause color shifts, modulating the duty cycle allows the LED to operate at its nominal current during the “ON” portion of the cycle. Because the frequency response of human vision is limited, using a PWM frequency of 250 Hz avoids the perception of flicker for the observer.</p> <p>The LED model has an internal monitor for the "perceived" light output (blue waveform), which is a low-pass filtered version of the instantaneous light output. The filter pole frequency is set to 15 Hz to represent the bandwidth of the human eye. The value of the dimmer setting (green waveform) is increased from 10% to 90% at time 100msec. The LED current pulses (red waveform) are shown before and after the duty-cycle transition.</p> <p>Part of this design is based on a dimmer schematic found on-line:</p> <p><a href="http://www.555-timer-circuits.com/led-dimmer.html">http://www.555-timer-circuits.com/led-dimmer.html</a></p> <p>That original circuit is actually incorrect, one of the diodes connected to pin 7 on the 555-Timer needs to be reversed. There was a comment from a reader who said he built the circuit as shown and it didn’t work. This is a good example of the value of simulating circuits before building hardware!</p> About text formats Tags 555 TimerLEDpotentiometer Select a tag from the list or create your own.Drag to re-order taxonomy terms. License - None - What's this? Design Titleby usman.qasim1994 × Embed Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/embed-design/397033"></iframe> Embed Live Design Copy Embed Code <iframe allowfullscreen="true" referrerpolicy="origin-when-cross-origin" frameborder="0" width="100%" height="720" scrolling="no" src="https://explore.partquest.com/node/397033"></iframe> Share a Link Copy URL https://explore.partquest.com/node/397033 Pagination Previous page ‹‹ Page 2 Next page ››