Make: Electronics relay oscillator


I put together the breadboarded relay oscillator experiment from the excellent Make: Electronics book, using the parts from the Make: Electronics Components Pack 1, both of which are available from the Maker Shed. Since the power adapter in the kit has some barrel plugs I didn’t want to chop off, I came up with a way to adapt it for use with the terminal screws on the supplied breadboard.

6 thoughts on “Make: Electronics relay oscillator

  1. says:

    Incredibly, I was sitting down to make my first relay oscillator when I thought “I guess I’ll just check my RSS reader first to see if there’s any…WHAT THE!”

    1. John Park says:

      That’s awesome, I love accidental clairvoyance. I followed your link to your blog as I was thinking how terrifically hungry I am, and there you have some photos of a delicious looking pizza. AAARG!

  2. Noah Ratcliff says:

    Thank you SO much for that tip on the wall warts. You saved me from cutting a whole lot of heads off.
    But I do have a question… If I used a capacitor with a smaller capacitance, say 100 micro farads would it oscillate faster? Also, would I be able to control the speed of oscillation by putting a pot between the negative pin of the coil and negative lead of the capacitor to slow the charge time?

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John Edgar Park likes to make things and tell people about it. He builds project for Adafruit Industries. You can find him at and twitter/IG @johnedgarpark

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