This is a continuation of my previous article regarding class d amp using 555 timer chip. Looking back to several schematics on that article, some of you may wonder why I include another 555 as U2 in the drawing. The main purpose of this U2 is to establish constant frequency trigger on pin 2 of U1 in such a way of maintaining stable PWM carrier frequency during audio input modulation. Continue reading “Class D amp made easy with 555 timer IC”