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Project: Old Phone Ringer

  1. Jan 12, 2012 #1
    Hello All, I am working on a project to get a old phone (from the 50's) to ring. The problem that I have is ringer voltage is 80V @ 20-25 Hrtz. I am trying to come up with a really cheap way to achieve this. I was thinking of getting a variac to set the voltage at 80V but I would still need a way to alter the frequency. Any help will be much appreciated!
     
  2. jcsd
  3. Jan 12, 2012 #2
    Get an SCR dimmer. Arrange it to be triggered by a microprocessor (like a 16F684) where it counts AC cycles and triggers on every third one. If you delay the trigger for the right length of time in the AC cycle you will get the 80 volts RMS too.
     
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