On Sun, 29 Mar 2009 10:32:59 -0700 (PDT), svu geek
wrote:

I need to buy a multimeter. I noticed that for the resistance some
have 2000k and some have 20M, which I believe are totally different.
Which one is better to have? Or does it even matter? I'm mostly
interested in testing something that's around 2M.

The resistance you plan measure, 2M ?, had nothing to do with the
resistance of the meter. All mulitmeters can measure a wide range of
voltages, probably enough for anything you'll want, unless your
intrests broaden a lot. (For example, you need a special probe to
measure the 25000 volts on a color tv picture tube, but you will never
do that. And if you need to see if there's voltage to a picture tube,
you can just put a little neon bulb in a soda straw, and hold it near
the thick wire. If it lights up, you have voltage. )

So I don't know if
it matters which multimeter I get.

Just for the record, on an analog meter and iiuc on a digital meter,
it's 2K or 2meg ohms/volt, ohms per volt. I think that means that the
resistance in the meter circuit is 2K or 2M times the greatest value
at the right end of each analog scale. That is, the resistance
changes for each dial setting. Not sure what it means in digital, but
something parallel.

I hate to like new-fangled stuff, but I do in this case. I think you
can easily learn to ignore phantom voltages in AC current and that is
pretty much the only drawback to high impedance meters. While there
are high-impedance analog meters (Like FET-VOMs) they are quite
uncommon. Most are digital and the advantages of digital are
auto-polarity (no need to get the red and black right when measuring
voltage), auto-zeroing and auto-maximum for resistance measuring, and
for some slightly more expensive meters, auto-ranging (no need to set
a dial to the 2, 20, 200, or 2000 volt scale, etc. It figures it out)

Analog don't and can't afaik have any of these things.

OTOH, analog have the advantage that you can put the meter on
resistance and watch a capacitor charge or discharge. After a while,
I felt I could tell a good cap by the way the needle moved. You can
also watch a discharge with the meter on DC voltage, but iirc for all
but really small caps, it takes too long.


It's nice to have a continuity tester with a buzzer built-in, so you
don't have to look at the meter for this simple task. The very cheap
Harbor Freight meters don't have that, and maybe some others don't, so
if you want that, check if it has it.