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Class D Amplifier

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A Digital or Switch Mode Amplifier

Analogue circuits are less efficient and produce more waste heat that digital circuits.

The Class D Amplifier converts analogue audio into a switched pulse width modulated digital signal at a frequency well above the range of human hearing (at least 44kHz). The amplifier works with close to 100%efficiency. The high frequency information is filtered out before the output is fed to the loudspeakers.

This circuit and simulation is running over 100 times slower than a real audio amplifier.
The triangle wave frequency should be well above 44 kHz so the coupling capacitor could be much smaller at 1 µF.
The load resistance would be 8 Ω speakers.
A low pass filter should be placed between the amplifier and speakers to remove the 44 kHz component.
This circuit seems to be difficult to build in real life.

Class D Amplifier.gif

For the Falstad Circuit Simulation, CTRL+Click Class D Amplifier
In options, check European Resistors and uncheck Conventional Current.
Use the sliders to adjust the bias.

Alternatively view Class_D_Amplifier.txt.
Save or copy the text on the web page. Import the saved or copied text into the Falstad simulator.

Here is the new HTML5 Simulator Site.