Square Wave Generator design help.

Discussion in 'The Projects Forum' started by idmiller, Mar 16, 2014.

  1. idmiller

    Thread Starter New Member

    Jun 16, 2013
    Hello, I had great success from this group in the past (thank you to all who posted in my last thread) and I have recently started learning some new devices. I am self teaching myself as I go along. I have a laser that I use with my telescope that pulses on from 1hz to 900+. While this circuit works the way I want it to it has a lot of annoyances to it. Like half of the rotation of the pot only moves the frequency 3hz then it ramps up dramatically with the rest of the range. I recently learned some more about op amps and octo-couplers and was wondering if someone had some time to talk with me about what was and was not possible with these. Again I'm not asking for someone to give me the answer but to help with the right choice of devices, and maybe a few snack crackers. Right now I have no circuit designed as I am not sure this is possible and if it's not possible I already have something that works.

    I would like a variable freq/duty square wave generator.
    This output will control an octo coupler
    Which will control the power source for the laser.

    I am looking for a range of .5hz to 60hz with a duty cycle of 50%+-10%
    Using either
    Dual op amp LM358P
    Quad op amp LM324N
    octo EL817 B312

    Thank you in advance.
  2. Jony130

    AAC Fanatic!

    Feb 17, 2009
    You can try this circuit
  3. idmiller

    Thread Starter New Member

    Jun 16, 2013
    Wow. Jony while I wasn't looking for someone to do the work for me that circuit looks like it will be perfect. I'll order the few missing parts namely the pots. And will let you know how it works.