DIY Circuit Design: Pulse Width Modulation (PWM) DIY Circuit Design: Pulse Width Modulation (PWM) September 30, 2013 By Engineers Garage . The PWM is a technique which is used to drive the inertial loads since a very long time simple example of an inertial load is a motor. Apply the power to a motor for a very short period of time and then turn off the power: it can be observed that the 3 Amp PWM DC Motor Controller Schematic Circuit Diagram Aug 23, 2019This affordable PWM DC Motor controller can control any PMDC motor specified at 12 V to 30 V and 3 Amps max. Motor direction is controlled with a slide switch and motor speed, with an ordinary potentiometer. The circuit diagram in Figure 1 shows ICs type LMD18200 and SG3525 at the heart of the circuit.