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Watson A.Name - 'Watt Sun'
 
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Default Turn Your Power Supply into an Ohmmeter - It's Free!

In article tdvRa.71417$OZ2.13017@rwcrnsc54,
mentioned...

"Watson A.Name - 'Watt Sun'" wrote in message
.. .
In article ,
mentioned...
"Mark D. Zacharias" wrote in message
link.net...
Congratulations. You proved Ohm's Law works.

Actually it is the resistance formula that works. What you think

is
Ohm's (V=IR) is not. See the links below and a good physics book. Ratch
http://maxwell.byu.edu/~spencerr/websumm122/node50.html

http://www.launc.tased.edu.au/online...Resistance.htm

And both Mark Z and Ratch are barking up the wrong tree. If they were
to reread my post below, they would see that I used the formula,
R=V/I, which in both URLs above was shown first and named Ohm's Law.
Doh.


No, both the above URLs make a point of saying that R=V/I is not Ohm's
law, and the first refers to R=V/I as the resistance formula. In other
words, Ohm's law referring to V=IR is a misnomer. The second URL points out
that Ohm's law really and truly refers to the resistive linearity of a
material. Dah.


This is *still* pointless. I *never* claimed that I was doing
*anything* with _Ohm's_Law_!! Quit trying to put words in my mouth!
See my OP below.

[snip]
Ratch


Of course it's only as accurate
as your meters, then you have to use your calculator.

Sorry, but give me a decent digital multimeter.

Your method is certainly worth remembering in a pinch.

Mark Z.

"Watson A.Name - 'Watt Sun'" wrote in message
.. .
I got tired of switching the leads of my DMM. Suddenly if dawned on
me that I can just set the power supply to 10.0V for exaample, and
read the current, and then divide the voltage by the current to find
the resistance. Like I put a resistance on the PS, it reads 10.0V

and
the current is .018A, so 10 / .018 gives 555.6 ohms. Must be a 560
ohm resistor.

I turned my PS into an ohmmeter - FREE!

Hee-hee - Work smarter, not harder!

Of course, make sure the current stays low so the resistance doesn't
overheat. For low resistances use a volt or less.


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