Know your specs when evaluating multimeters  Disgnostic Pulse
One multimeter is the same as the next, right? Not so. While a
multimeter remains as one of your best diagnostic investments,
it’s one you shouldn’t take lightly. With just a little insight
into what to compare, you’ll be better prepared when you plunk
down your hard-earned cash.  Here’s a look at some of the most
common meter specs, and what they really mean when comparing one
meter against another. There’s a lot of jargon flying around
when it comes to meter specs, but with a little patience you
should be able to frame it into understandable terms.
Expressed in megohms (millions of ohms), this is the amount of
resistance that the multimeter's circuitry yields during
testing. It’s critical for a couple of reasons. A high-impedance
multimeter (at least 10 megohms) only causes minimal loading of
the circuit under test. This is extremely critical on today's
electronically controlled systems. If a low-impedance meter were
used, circuit readings wou