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triac current limiter

Discussion in 'Glowing Bottle Tube Amp Forum' started by dogmeat, Oct 29, 2020.

  1. dogmeat

    dogmeat Friend of Leo's

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    anybody made a limiter using a triac? seems like that would be a kool thing for testing amp builds & repairs. got a diagram & some specs?
     
  2. Bill Moore

    Bill Moore Tele-Afflicted Silver Supporter

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    Seems the pulsing would cause noise!
     
    Digital Larry likes this.
  3. printer2

    printer2 Poster Extraordinaire

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    Why would giving the amp reduced, really dirty power be desirable. Diagram? Hook up the amp to a $10 light dimmer.
     
  4. uriah1

    uriah1 Telefied Gold Supporter

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    Isn’t that what Eddie Van Halen used. Some blogs on it
     
  5. BobbyZ

    BobbyZ Doctor of Teleocity

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    Pretty hard to beat a light bulb limiter. You get a dead short, you get a bright bulb, no blown fuse in the amp. So you have plenty of time to figure out where the short is.
    All you gotta do is put an old school bulb in serious with the AC going into the amp. In its simplest form take an extension cord, cut a wire (that ain't the ground) strip the ends and put um on a light bulb socket. There's plans online for much more elaborate set ups but they all work the same way.
    Limiting voltage into an amp is another matter. For testing you really want something that'll safely take the current if the amp has a short. A cheap light bulb just acts like it would with the switch closed, no smoke, just light.
     
  6. alnicopu

    alnicopu Friend of Leo's

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    This^^^. I have been working with triac circuits for many years. Very dirty ac gated thru them. Lotsa pulsating. They require a lot more supporting components when used as a current limiter than the light bulb trick. Another issue is when they fail, they usually wont STOP conducting and need to be fused for when they do. See that a lot. Good for switching on a heater type circuit in conjunction with a thermistor or a dimmer switch where all you care about is getting the ac turned on and off with a low voltage trigger. On the other hand, a cool project in its own right. Along the way you’ll learn about hysterisis, firing angles and such.
     
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