Another clever trick from the world of electronics, Pulse Width Modulation is a simple method for controlling analog devices via a digital signal. It’s also a very efficient way to drive motors, lamps, LEDs, & more.
If you’ve ever faded an LED with an Arduino – you’ve used PWM. But you don’t need a microcontroller to generate a PWM signal. The ever-versatile 555 timer chip can be configured to modulate its output duty cycle in response to a potentiometer – with the help of some relatively simple circuitry. Or for a more robust solution, consider the DC to Pulse Width Modulator kit suitable for sending up to 6.5A of current and built around the Motorola SG3525 – a chip dedicated to the art of PWM.