Mike DonnellyDesigner19 × Mike Donnelly Member for 8 years 6 months 1,221 designs 5 groups Original member of the PartQuest Explore development team. Modeling and Applications Specialist Vote up! Vote down! Points +26 986 views total 806 views today Title Description <p>This "Live" example design includes a simple analog electronic amplifier, intended only to demonstrates the importance of multi-discipline system modeling.</p> <p>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.</p> <p>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!</p> <p>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.</p> <p>* Note: Please refer to this companion example, that shows the input impedance frequency response of the loudspeaker alone:</p> <p>https://www.systemvision.com/design/loudspeaker-only-frequency-response</p> About text formats Tags LoudspeakerAmplifierelectro-mechanical resonanceBDP947NCV20071 Op-AmpBDP947 NPN TransistorMechatronicsmagnetic actuator Select a tag from the list or create your own.Drag to re-order taxonomy terms. License - None - What's this? Please login or register to post comments You must be a registered user to add a comment. Design Titleby Mike Donnelly × 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/6116"></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/6116"></iframe> Share a Link Copy URL https://explore.partquest.com/node/6116
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