Discussing Pulse-Width Modulation

[Michael Kleinigger] posted a lengthy discussion on Pulse-Width Modulation that goes beyond the traditional beginner tutorial. He starts a bit of background info on PWM and a tip about using a camera to judge frequency and duty cycle of LEDs. From there it’s down the rabbit hole with some testing of power-loss versus frequency.

When you change from frequencies of 50 Hz to 1 MHz how does the parasitic power loss from switching affect the overall efficiency of the circuit? It turns out there’s a rather large amount of loss at the highest level, around 1.5 mW. The greatest balance of low power loss and elimination of flicker seems to be right in the 300-500 Hz range.


  1. Forrest C. Shields II says:

    It seems that the site that the link refers to is permanently down. Here is a link to the article from the Wayback Machine (archive.org) as it existed on September 25, 2010:


    All the images are broken and the formatting looks terrible, but the text of the article is there.

  2. akismet-16bc517122f7a78973b26bef51f1b331 says:

    Thanks for the reminder Forrest… my dynamic DNS service decided not to be free anymore, and ultimately stopped forwarding. The article is still live and in its original form here: http://www.nlvocables.com/blog/?p=188

  3. Mike says:

    Thanks for the reminder Forrest. My dynamic DNS service decided to no longer be free… The original article can be found here: http://www.nlvocables.com/blog/?p=188

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