Plasma Speaker Not Working

Discussion in 'The Projects Forum' started by magnet18, Mar 19, 2011.

  1. magnet18

    Thread Starter Senior Member

    Dec 22, 2010
    As usual, nothing I do works.
    I'm trying to build a plasma speaker, got most of the construction done, but I can't get the thing to work. I honestly have no idea what might be wrong with it. I originally had one of the windings of the gate driver transformer wired backwards, so I fixed that and replaced the chip and FET's, still no dice.

    I don't really expect anyone to search through my circuit visually, but if there is anything that jumps out at you as being bad, please let me know.

    Heres the schematic
    And heres a couple pics of the board, the lines running out should provide reference to orientation.

    Hopefully you see something simple jump out at you.
  2. Wendy


    Mar 24, 2008
    For a reality check put speakers where the low voltage coil is at. Unless I misread the circuit entirely shouldn't there be audio there?
  3. eblc1388

    AAC Fanatic!

    Nov 28, 2008
    Same here. But that never bother me because I can usually make it works after correcting a few silly mistakes.

    Power off the circuit. Temporally threads and wraps about 10 turns of thin wire to the gate drive transformer and connects the ends to a DVM on AC voltage range.

    Power ON the circuit and check if you have got any reading on the meter.
  4. shortbus

    AAC Fanatic!

    Sep 30, 2009
    I'm no kind of expert,so probably wrong. In another thread a month or two ago, it was talked about using heavily insulated wire, like the wire on your gate drive transformer instead of magnet wire. The gist of the thread was the capacitance that was a by product of the heavy insulation. Is it possible that the extra capacitance in your transformer is enough to throw off the circuit?

    In circuits like switching power supplies and the like the never use anything but magnet wire for the coils.
  5. blueroomelectronics

    AAC Fanatic!

    Jul 22, 2007
    You're missing caps on the regulator. They're not optional.
  6. Kermit2

    AAC Fanatic!

    Feb 5, 2010
    It might have found another place to form the arc.

    Power it up in a room where you can turn off the lights and have total darkness. You might be able to see a glow coming from somewhere around the transformer. Maybe under a wrap of insulation on the coil.

    Assuming of course the circuit is working. :)
  7. magnet18

    Thread Starter Senior Member

    Dec 22, 2010
    Thanks for the assistance guys, but I eventually gave up on this design, along with about 3 other's since then, and I just ripped the 555 portion off of a flashing light circuit and it works to create an arc. I should be able to bump it up to ultra-sonic tomorrow and audio-modulate it with a cap on pin 5.
  8. akthewayiam

    New Member

    May 19, 2011
    Well there is a simple solution,just separate the ic power supply ie the regulator's one and the mosfet power supply including separating both the grounds.It worked for me with the same corcuit as of yours.:D
  9. Wendy


    Mar 24, 2008
    This thread is pretty old. He got it working and mentions it on another thread.