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This "Live" example design includes a simple analog electronic amplifier, intended only to demonstrates the importance of multi-discipline system modeling.

A swept frequency response test, from 40 Hz to 1000 Hz, shows the effect of the complex amplifier loading by the voice-coil and speaker-cone dynamics*. The electro-mechanical resonances strongly affect the current that must be supplied, in order to maintain a flat (controlled) output voltage over the specified frequency range. For example, the current in the voice-coil reaches a null at time 0.1 seconds, which corresponds to the effective "spring-mass" resonance frequency (60 Hz). The loudspeaker reaches its minimum impedance around 600 Hz, or at 0.6 seconds where the peak load current is observed.

The simulation results also show that the average power (q1/npn/pwr_avg) in the BDP947 BJT exceeds its 5 Watt rating across the entire range, but especially at lower frequencies. The red "hot part monitor", with the junction to ambient thermal resistance set to 10 C/Watt, as given in the datasheet, shows the part temperature rising to over 100 C. These diagnostic indicators make it obvious that we need a bigger transistor!

All of the parameters in blue can be changed by the user and a new simulation run. The updated scope waveform results will show the effect of that change. You can change the electrical resistance and inductance of the voice-coil, as well as the speaker cone mass and linear spring rate that affect the resonance frequency.

* Note: Please refer to this companion example, that shows the input impedance frequency response of the loudspeaker alone:

https://www.systemvision.com/design/loudspeaker-only-frequency-response

Copy of Loudspeaker with Simple Amplifier - on Sun, 11/15/2020 - 06:24

bbenoit1625
Designer197752

bbenoit1625

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6 years 8 months

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Description

This simple* analog electronic amplifier design demonstrates the importance of multi-discipline system modeling. A swept frequency response test, from 40 Hz to 1000 Hz, shows the complex amplifier loading effect of the voice-coil and speaker-cone dynamics. The electro-mechanical resonances strongly affect the current that must be supplied, in order to maintain a flat (controlled) output voltage over the specified frequency range. For example, the current in the voice-coil reaches a null at time 0.1 seconds, which corresponds to the effective "spring-mass" resonance frequency. The loudspeaker reaches its minimum impedance around 600 Hz, or near 0.6 seconds, where the peak load current is observed.

Normalized component stress monitoring signals are provided in all “datasheet specified” electronics models. For example, the simulation results show that the average power (bjt1/pwr_avg) in the BDP947 NPN BJT exceeds its 5 Watt rating across the entire range, but especially at lower frequencies. The corresponding stress monitor (bjt1/stress_ratio_power_avg) normalizes the transistor's average power relative to its 5W rating, so it is easy to see that the component is stressed (i.e. stress_ratio_power_avg &gt; 1.0). Also, the red "hot part monitor", with the junction to solder-point thermal resistance set to 10 C/Watt as given in the datasheet, shows the part temperature rising to well over 100 C. These diagnostic indicators make it obvious that we need a bigger transistor!

*Note: This is not intended to be a practical amplifier design. There is no blocking capacitor at the output, so it allows undesirable DC current into the voice coil. The purpose is to focus attention on the dynamic characteristics of the loudspeaker and not the circuit itself.

Copy of Loudspeaker with Simple Amplifier - on Tue, 10/06/2020 - 17:52

juan.mendozar
Designer235029

juan.mendozar

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4 years 3 months

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Description

This "Live" example design includes a simple analog electronic amplifier, intended only to demonstrates the importance of multi-discipline system modeling.

A swept frequency response test, from 40 Hz to 1000 Hz, shows the effect of the complex amplifier loading by the voice-coil and speaker-cone dynamics*. The electro-mechanical resonances strongly affect the current that must be supplied, in order to maintain a flat (controlled) output voltage over the specified frequency range. For example, the current in the voice-coil reaches a null at time 0.1 seconds, which corresponds to the effective "spring-mass" resonance frequency (60 Hz). The loudspeaker reaches its minimum impedance around 600 Hz, or at 0.6 seconds where the peak load current is observed.

The simulation results also show that the average power (q1/npn/pwr_avg) in the BDP947 BJT exceeds its 5 Watt rating across the entire range, but especially at lower frequencies. The red "hot part monitor", with the junction to ambient thermal resistance set to 10 C/Watt, as given in the datasheet, shows the part temperature rising to over 100 C. These diagnostic indicators make it obvious that we need a bigger transistor!

All of the parameters in blue can be changed by the user and a new simulation run. The updated scope waveform results will show the effect of that change. You can change the electrical resistance and inductance of the voice-coil, as well as the speaker cone mass and linear spring rate that affect the resonance frequency.

* Note: Please refer to this companion example, that shows the input impedance frequency response of the loudspeaker alone:

https://www.systemvision.com/design/loudspeaker-only-frequency-response

Copy of Common Emitter Amplifier - on Sun, 10/04/2020 - 20:29

clo21
Designer235403

clo21

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4 years 2 months

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Copy of Class A Amplifier - on Wed, 09/16/2020 - 12:24

briangato.bb
Designer234763

briangato.bb

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4 years 3 months

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Copy of Loudspeaker with Simple Amplifier - on Sat, 09/12/2020 - 13:55

pdhobby1213
Designer234706

pdhobby1213

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4 years 3 months

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Description

This "Live" example design includes a simple analog electronic amplifier, intended only to demonstrates the importance of multi-discipline system modeling.

A swept frequency response test, from 40 Hz to 1000 Hz, shows the effect of the complex amplifier loading by the voice-coil and speaker-cone dynamics*. The electro-mechanical resonances strongly affect the current that must be supplied, in order to maintain a flat (controlled) output voltage over the specified frequency range. For example, the current in the voice-coil reaches a null at time 0.1 seconds, which corresponds to the effective "spring-mass" resonance frequency (60 Hz). The loudspeaker reaches its minimum impedance around 600 Hz, or at 0.6 seconds where the peak load current is observed.

The simulation results also show that the average power (q1/npn/pwr_avg) in the BDP947 BJT exceeds its 5 Watt rating across the entire range, but especially at lower frequencies. The red "hot part monitor", with the junction to ambient thermal resistance set to 10 C/Watt, as given in the datasheet, shows the part temperature rising to over 100 C. These diagnostic indicators make it obvious that we need a bigger transistor!

All of the parameters in blue can be changed by the user and a new simulation run. The updated scope waveform results will show the effect of that change. You can change the electrical resistance and inductance of the voice-coil, as well as the speaker cone mass and linear spring rate that affect the resonance frequency.

* Note: Please refer to this companion example, that shows the input impedance frequency response of the loudspeaker alone:

https://www.systemvision.com/design/loudspeaker-only-frequency-response

Copy of Loudspeaker with Simple Amplifier - on Fri, 09/11/2020 - 01:32

pdhobby1213
Designer234706

pdhobby1213

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4 years 3 months

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Description

This "Live" example design includes a simple analog electronic amplifier, intended only to demonstrates the importance of multi-discipline system modeling.

A swept frequency response test, from 40 Hz to 1000 Hz, shows the effect of the complex amplifier loading by the voice-coil and speaker-cone dynamics*. The electro-mechanical resonances strongly affect the current that must be supplied, in order to maintain a flat (controlled) output voltage over the specified frequency range. For example, the current in the voice-coil reaches a null at time 0.1 seconds, which corresponds to the effective "spring-mass" resonance frequency (60 Hz). The loudspeaker reaches its minimum impedance around 600 Hz, or at 0.6 seconds where the peak load current is observed.

The simulation results also show that the average power (q1/npn/pwr_avg) in the BDP947 BJT exceeds its 5 Watt rating across the entire range, but especially at lower frequencies. The red "hot part monitor", with the junction to ambient thermal resistance set to 10 C/Watt, as given in the datasheet, shows the part temperature rising to over 100 C. These diagnostic indicators make it obvious that we need a bigger transistor!

All of the parameters in blue can be changed by the user and a new simulation run. The updated scope waveform results will show the effect of that change. You can change the electrical resistance and inductance of the voice-coil, as well as the speaker cone mass and linear spring rate that affect the resonance frequency.

* Note: Please refer to this companion example, that shows the input impedance frequency response of the loudspeaker alone:

https://www.systemvision.com/design/loudspeaker-only-frequency-response

Copy of Compare Cascode vs. Single MOSFET Amplifier - on Tue, 09/08/2020 - 13:17

alpha_peach
Designer234625

alpha_peach

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4 years 3 months

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Description

This example shows the bandwidth improvement that results from a cascode amplifier configuration (right-side circuit), compared to a single transistor amplifier configuration (left side).

In these circuits, identical transistor models are used. They are "datasheet" based behavioral models with typical small-signal NFET characteristics. This includes an internal Miller capacitance or Crss, which is set to 10 pF.

In the single transistor circuit, the Miller Theorem states that the effective value of Crss is increased by a factor of (1.0 + A), where A is the gain of the amplifier. In this case the factor is (1.0 + gfs * Rload), or 16x, so the effective Crss = 160 pF. Then the low-pass RC time constant of the input source resistance and the net input capacitance sets the amplifier bandwidth at just under 2 MHz.

For the cascode amplifier, the voltage at the drain of transistor m2 has only very small variation, so the Miller effect is largely suppressed for that device. Transistor m3 amplifies these small voltage changes, but because the current in the Miller capacitance of m3 is drawn from the low impedance gate bias circuit, it does not limit the bandwidth of the amplifier.

You can move the probes around and look at the time-domain or frequency-domain signals at any point in the circuit, to gain more understanding of these component interactions.

Copy of Loudspeaker with Simple Amplifier - on Wed, 08/19/2020 - 15:31

aungtun
Designer211422

aungtun

Member for

5 years 10 months

9

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Description

This "Live" example design includes a simple analog electronic amplifier, intended only to demonstrates the importance of multi-discipline system modeling.

A swept frequency response test, from 40 Hz to 1000 Hz, shows the effect of the complex amplifier loading by the voice-coil and speaker-cone dynamics*. The electro-mechanical resonances strongly affect the current that must be supplied, in order to maintain a flat (controlled) output voltage over the specified frequency range. For example, the current in the voice-coil reaches a null at time 0.1 seconds, which corresponds to the effective "spring-mass" resonance frequency (60 Hz). The loudspeaker reaches its minimum impedance around 600 Hz, or at 0.6 seconds where the peak load current is observed.

The simulation results also show that the average power (q1/npn/pwr_avg) in the BDP947 BJT exceeds its 5 Watt rating across the entire range, but especially at lower frequencies. The red "hot part monitor", with the junction to ambient thermal resistance set to 10 C/Watt, as given in the datasheet, shows the part temperature rising to over 100 C. These diagnostic indicators make it obvious that we need a bigger transistor!

All of the parameters in blue can be changed by the user and a new simulation run. The updated scope waveform results will show the effect of that change. You can change the electrical resistance and inductance of the voice-coil, as well as the speaker cone mass and linear spring rate that affect the resonance frequency.

* Note: Please refer to this companion example, that shows the input impedance frequency response of the loudspeaker alone:

https://www.systemvision.com/design/loudspeaker-only-frequency-response

Copy of Loudspeaker with Simple Amplifier - on Thu, 07/30/2020 - 14:49

ghassanawada125
Designer233622

ghassanawada125

Member for

4 years 4 months

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Description

This "Live" example design includes a simple analog electronic amplifier, intended only to demonstrates the importance of multi-discipline system modeling.

A swept frequency response test, from 40 Hz to 1000 Hz, shows the effect of the complex amplifier loading by the voice-coil and speaker-cone dynamics*. The electro-mechanical resonances strongly affect the current that must be supplied, in order to maintain a flat (controlled) output voltage over the specified frequency range. For example, the current in the voice-coil reaches a null at time 0.1 seconds, which corresponds to the effective "spring-mass" resonance frequency (60 Hz). The loudspeaker reaches its minimum impedance around 600 Hz, or at 0.6 seconds where the peak load current is observed.

The simulation results also show that the average power (q1/npn/pwr_avg) in the BDP947 BJT exceeds its 5 Watt rating across the entire range, but especially at lower frequencies. The red "hot part monitor", with the junction to ambient thermal resistance set to 10 C/Watt, as given in the datasheet, shows the part temperature rising to over 100 C. These diagnostic indicators make it obvious that we need a bigger transistor!

All of the parameters in blue can be changed by the user and a new simulation run. The updated scope waveform results will show the effect of that change. You can change the electrical resistance and inductance of the voice-coil, as well as the speaker cone mass and linear spring rate that affect the resonance frequency.

* Note: Please refer to this companion example, that shows the input impedance frequency response of the loudspeaker alone:

https://www.systemvision.com/design/loudspeaker-only-frequency-response