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Subject: Re: Reducing contact resistance for low volt use?
Date: Sun, 15 Dec 2002 01:31:03 -0800
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John Muchow wrote:
> Yea, that current measuring thing is a pain. :-)
> I'll probably go Hall as I really don't have much resistance to play
> with here. I'll probably go with a 2 or 3 cell (in series) unit
> too...get the voltage up.
Most of your problems go away if you use 2-3 cells
It's that 10 milliohms at 1V that's killing you.
> One nice thing about the MOSFET load circuit is that I already have
> all the parts (except for the Hall-effect sensor) and I can easily
> work something up.
> I have also found 50-milliohm, 850-watt braking resistors (only $7
> each!) to use with a 5V, 100A power supply (in current limit).
> Hopefully I can get one of the supplies I saw for $20. The seller is
> checking if it has a current limiting pot somewhere. It does have
> voltage adjust though. I think that could be used in a pinch to
> auto-adjust the current, couldn't it?
yes, but it may not be simple. Still have to
measure the current somewhere.
The supply would get HOT, but I
> can add another couple of fans.
The supply won't get hot if you keep the voltage
near 5V. If it's a switcher,
it probably won't get hot at lower voltage
either....just go unstable ;-(.
> Time for lots of tests. :-)
> Thanks again for your help!
> John Muchow
Bunch of stuff For Sale and Wanted at the link
Tek 2465, TFT projector, ham radio, 30pS pulser
Tektronix Concept Books...
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