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  1. #1
    Senior Member Road Fan's Avatar
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    Halogen bulbs - DC or AC?

    May seem like a silly question, but are halogen bulbs able to run equally well on AC or DC sources?

  2. #2
    17yrold in 64yrold body
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    If the voltage/amperage are correct, I would think so. I have Niterider Halogens for bikes (DC source), and use them in different machines at work (AC source).

  3. #3
    Senior Member dougmc's Avatar
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    Quote Originally Posted by Road Fan View Post
    May seem like a silly question, but are halogen bulbs able to run equally well on AC or DC sources?
    They run equally well on AC or DC.

    In general, if the RMS (root-mean-square) voltage of an AC source matches the voltage of a DC source (and both sources can provide the needed amperage), the lights will have the same brightness. And as long as the AC frequency is high enough, there will be no flicker. (60 Hz is certainly high enough. 1 Hz is certainly too low for most bike lights. Ultimately, the frequency is rarely an issue.)
    Last edited by dougmc; 06-15-10 at 04:02 PM.

  4. #4
    Senior Member Road Fan's Avatar
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    Thanks, Doug, I was thinking it was based on effective voltage matching the DC voltage, but then I thought maybe the halogen activity is affected by the polarity reversals.

  5. #5
    Senior Member dougmc's Avatar
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    Nope. All the current does it make the filament hot, and that doesn't care what the polarity is.

  6. #6
    Senior Member Road Fan's Avatar
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    And hence the active halogen cycle, transporting tungsten, must be strictly driven by convection?

  7. #7
    Senior Member dougmc's Avatar
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    Quote Originally Posted by Road Fan View Post
    And hence the active halogen cycle, transporting tungsten, must be strictly driven by convection?
    Sure. What else would it be driven by? (Well, convection, Brownian motion, whatever.)

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