DC Bench supply.

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PackratKing

Joined Jul 13, 2008
847
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 ??
 
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jpanhalt

Joined Jan 18, 2008
11,087
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.

John
 

SgtWookie

Joined Jul 17, 2007
22,230
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.
 
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