DIYbanter - View Single Post - VOM -- How to use

Jim Yanik

wrote in
oups.com:

I have an active post about an attic fan, but noted that I don't
really know HOW to operate my "Portable 27-Range Multitester," an
analog VOM from about 1980-82.

It has an instruction manual that is about as clear as mud. I have
also read the appropriate pages in my "Readers Digest Fix-it Yourself"
book and my Time-Life "Complete Fix-it Yourself Manual"

What I don't understand is I have four dial settings areas basically
1. ACV 2. DCV 3. DCUA (the U is some south of wierd symbol, looks like
a U..sorta) 4. A Greek symbol, I think it's Omega (sorta of a squashed
upside down U).

ACV= AC voltage,what comes out of your home electric outlets.
DCV is DC voltage,,your car battery is DCV. (DC= direct curernt,meaing not
alternating current[AC].
Voltage is measured across the source.(parallel)

DCuA is DC current,uA= microamps(u= micro,small m= milli).
your meter should have several current ranges,the meter has to be in SERIES
with the current source.

Omega = OHMS, resistance measurement,or "continuity".
DONT apply any voltage or current in this mode,you will damage your meter.

Then there are four holes for the banana plugs. 1. COM, 2. V-(Omega?)-
A 3. AC 1KV 4. DC 1KV

COM= common,volts,amps and ohms share this terminal,usually the negative
side (black wire/lead)
V-A is volts/amps,the RED or positive lead.
AC 1KV is the 1000 volts range,high voltage,DC 1KV is for DC high volts.
these are separate jacks for safety reasons,to remind you you are working
on high voltage.

And of course the dial sections are a gobbly gook of RX1 or 1KV or .
25, you get the picture.

Rx1 is ohms scale reading times a multiplier of ONE. Rx10 would be the
scale reading times TEN,Rx100 times 100,etc.

All I want to know most of the time is if there is current flowing and
if there is, how much?

How do I measure that? Any good webpages? I think I looked last March
when I was doing some wiring work in the car, but I never found
anything. I ended up just using my continuity tester....even I can
figure out "when the bulb lights, there is juice!"

Yes,but the meter will tell you how much "juice". IOW,the voltage could be
low,like a 12V car battery that only reads 10V.

--
Jim Yanik
jyanik
at
kua.net