2008/11/21 Charles Geilfuss <charles.geilfuss@xxxxxxxxx>:
> Secondly, I removed the bottom and put a multimeter on the two leads
> going into the body of the rheostat. I get no reading unless I set the
> multimeter to the 200 ohm range. At the rheostat's lowest range I get a
> reading of 0.3 and at the highest range a reading of 0.6. So if I'm using my
> 4th grade math correctly, the range of the rheostat is 60 ohms to 120 ohms.
> Do these figures make sense to those of you out there who know what you are
> doing?
If it's in series with a 6V 20W bulb to control the brightness, then
your rheostat should have quite a low resistance - comparable to that
of the bulb when lit. 6V, 20W, I make that 3.33333 etc amps and
therefore a resistance, when lit, of 1.8 Ohms.
Normally, a digital meter will give a reading directly in the units
for the range, so 0.3 on a 200 Ohm range would be 0.3 Ohms. Also,
many meters will show a reading of 0.1-0.3 Ohms if you connect the
probes together.
What do you get between the ends of the rheostat, ignoring the wiper?
(and is it connected only at one end and the wiper?).
Of course, this could be misleading nonsense as I don't have the
circuit diagram.
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