Can I use a potentiometer in my Wire?

Discussion in 'General Electronics Chat' started by DkEnrgyFrk, Sep 25, 2011.

  1. DkEnrgyFrk

    Thread Starter New Member

    Feb 15, 2010
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    I have this potentiometer that I want to put in series with a lamp on my wire so that I can control the brightness of the lamp.

    My question is that I noticed on the potentiometer that it is stamped as a DC potentiometer. Can I use this component on my wire with an AC powered lamp?

    I don't know if that stamp was supposed to mean anything as far as a warning goes. Is there some reason I can't use DC components in an AC circuit?

    Thanks in advance.
     
  2. steveb

    Senior Member

    Jul 3, 2008
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    469
    Nooooo ! Very Dangerous! Don't do it!
     
  3. DkEnrgyFrk

    Thread Starter New Member

    Feb 15, 2010
    9
    0
    WHOA! Seriously?!

    Ok, what is going on with the DC component that makes it unusable in AC?
     
  4. steveb

    Senior Member

    Jul 3, 2008
    2,433
    469
    I just wanted to make sure I got the warning in first because dealing with AC (i'm assuming you're talking 110 VAC or 220 VAC) is dangerous in itself, and dropping power at that level is a fire hazard. I think this thread will be closed soon before long for those reasons.

    But, anyway, resistors can be used with AC or DC. That's not the issue. Typically light brightness is controlled with special semiconductor devices (called triacs) that control average brightness and power with much less heat than a simple resistor. Not only is the resistor a huge waste of power, but it is very very difficult to dissipate that heat in a safe way without a very large heat sink, which basically becomes a room heater when you are done. Well, incandescent lights are room heaters anyway, but basically there are better and safer methods.

    http://en.wikipedia.org/wiki/Dimmer
     
  5. DkEnrgyFrk

    Thread Starter New Member

    Feb 15, 2010
    9
    0
    ahh, ok. So, for the experiment I should use a wall dimmer switch and leave out the potentiometer.

    Thanks for the explanations. I figured there was a reason why that stamp was there...
     
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