Circuit Skills: Pulse Width Modulation

By Collin Cunningham
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Pulse Width Modulator P/N 120539

To control analog devices via a digital signal try pulse width modulation (PWM). It's a very simple method and is very efficient in driving motors, lamps, LEDs and more!

A perfect example of using PWM is if you've ever faded an LED with an Arduino:

Demonstrates the use of the analogWrite() function in fading an LED off and on. AnalogWrite uses pulse width modulation (PWM), turning a digital pin on and off very quickly, to create a fading effect.

However, you don't need a microcontroller to generate a PWM signal. The 555 timer chip can be configured to modulate its output duty cycle in response to a potentiometer – with the help of some simple circuitry.

For a more robust solution, you may want to 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.

Of course, Collin would be denying his own nature if he didn't mention at least one audio-related application. PWM comes in handy for generating simple sounds and melodies from a microcontroller.

Arduino Simple Sounds
Wavetable Melody Generator

Build Your Own DC to PWM Kit

Manufacturer Product Number: K8004
Manufacturer: Velleman

Click here for K8004 data sheet

If you decide to build the DC to pulse width modular kit, we'd like to hear about your results!
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