DC Bench supply.

Discussion in 'General Electronics Chat' started by PackratKing, Oct 6, 2008.

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  1. PackratKing

    Thread Starter Well-Known Member

    Jul 13, 2008
    Hey y'all !!

    I recently scored a bunch [ 10 ] 200 ohm, at least 100 watt, 1" dia. 12" long -- ceramic resistors. These have an exposed strip along the side, for an adjustable tap, but there is no indication of how much amperage the coil is good for................The wire, I assume similar to NiChrome is .010 dia. 5 amps would be nice.

    I want to rig one with a carbon motor brush as a slider, to make an ersatz rheostat, fed by std. 120v AC to a rectifier bridge, for a light duty DC test bench supply. I have the liberty of burning one up to discover their limit, but would rather not roll that way.

    Sound reasonable ??
    Last edited: Oct 6, 2008
  2. jpanhalt

    AAC Fanatic!

    Jan 18, 2008
    5A at 200 ohm takes a of of voltage, doesn't it? Can you estimate the current rating from the wattage, assuming 100 W? That is I^2R = W. From that, I get 0.7 A.

  3. SgtWookie


    Jul 17, 2007
    Absolutely not.

    What you propose is extremely dangerous. No isolation from the mains.

    The only safe way is to use an isolation transformer.

    Please do not propose such foolishness again.
  4. beenthere

    Retired Moderator

    Apr 20, 2004
    With no isolation from the line, the proposal is asking for injury. This is much too dangerous to use.
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