3pdt true bypass and power switching

Discussion in 'General Electronics Chat' started by stoopkid, Aug 13, 2011.

  1. stoopkid

    Thread Starter Member

    Mar 3, 2011
    136
    1
    I am going to get a 3pdt switch for a pedal I am making. Here is the pedal schematic:
    http://solgrind.files.wordpress.com/2008/02/zvex-fuzzfactory-rev1-1.gif

    I want to use true bypass:
    Http://www.muzique.com/lab/truebypass.htm

    So my userstanding is that two of the poles go to true bypass and one pole for power switching. But I also want an LED indicator. Putting the LED in series with the 9v battery will lower the voltage.

    If I put the LED in parallel with the rest of the circuitry would I have issues with either the LED or the pedal circuitry carrying the whole load and messing with the other, or anything like that? Or is it okay to just put them parallel on the same switch pole?

    Thanks
     
  2. ErnieM

    AAC Fanatic!

    Apr 24, 2011
    7,389
    1,605
    musique's switch is a DPDT, two poles. No power switching is shown.

    You could use the third pole of a 3PDT switch to control the LED. No issues there.
     
  3. stoopkid

    Thread Starter Member

    Mar 3, 2011
    136
    1
    Right, but if you look at the first link, that circuit will still be using the 9v battery power even if the input circuit is broken. So I need two poles for bypass and the third pole for the battery so it does not drain. I'm asking if I can just throw an LED in parallel to the rest of that circuit off the 9v without an issues.
     
  4. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    You could use the 3rd pole of the switch for connecting/disconnecting the battery to the circuit.

    And you can place an LED in series with a current limiting resistor, in parallel with the rest of the circuit.

    I suggest that you use a rather large resistor, like around 2k-2.3k - or the LED will drain the battery more rapidly than you would like.
     
  5. stoopkid

    Thread Starter Member

    Mar 3, 2011
    136
    1
    Excellent, thank you.
     
Loading...