Send this PWM signal to a MOSFET or something, and you have the simplest class D amp in existence. They’re so simple, you can buy a class D amp chip for $3, but [George] thought that would be ...

A class D amplifier simply switches transistors of ... ATtiny microcontroller to drive a set of MOSFETs. In [Rouslan]’s circuit, the audio signal is passed into the analog input of an ATtiny45.

Because pulse modulation output signals are either on or off, Class D amplifiers produce far less heat than analog amplifiers. Reaching efficiencies greater than 90% compared to only 50% for ...