Your checkout readings from the Tenma model are pretty good. It's definitely
annoying when DMMs hunt for a reading.
Tenma was a generic/clone product company that's turned into a fairly widely
recognized brand name.
The no-name brands that sell in about the $6 and up range are what quite a
few sellers are offering lately. The term digital doesn't assure accuracy,
and doesn't much matter if the device is a DMM or a bathroom scale.

A good practice is to take test readings of known voltages before circuit
testing begins. When weird/unexpected readings are encountered, the user
needs to determine why, to be able to proceed safely.

Simpson, Triplett, Weston have all made durable, reliable analog meters (and
most still do).
Older analog or digital meters are great if you're the original owner, that
way you could be sure that they haven't been OV'd or abused. I still have a
working one that was new in about '73.
Aged meters (decades) shouldn't be expected to be as accurate as when they
were manufactured because component values will drift with age, but their
durability is their real value (and they can often be recalibrated or
repaired to their original accuracy).
For home/shop wiring voltages, an error of a few volts isn't very critical.

Beckman made some of the highest quality DMMs, although they're produced
under Wavetek now (and look like a design school project for a TV/VCR/?
all-in-one all purpose remote control).
The Beckman Industrial 100-4000 series were extremely well built. Not many
handheld DMMs had a 1000-1500VAC range, which is important for 460+ 3-phase
AC (because the phase-phase peaks exceed the 750VAC maximum input of meters
with a 750AC max. range).
Old Beckman DMMs can be problematic.. the switches may have become oxidized,
or the LCD holders may not be as tight as neccessary to maintain
consistently clear readings (missing display segments).

WB
.................

"Mike Henry" wrote in message
...
I guess I expected something other than absolute zero VAC, but 14 and 70
VAC
had me a bit concerned. Without cause apparently.

Your "no lead" test was interesting. The Tenma (import from Gaingers,
probably) that I was using most of the time is an autoranging DMM and
reads
around 1-2 MV. An old Heathkit (an actual kit) from around 30 years ago
reads 0.1-0.2 MV reads exactly 0 on all of it's ranges. Guess I'll use
the
Heathkit next time and maybe look around for an analog in good shape.

Is Simpson a good brand?

Mike


"Wild Bill" wrote in message
...
Yes, an analog volt meter is definitely more reliable than a lot of DMMs
for
AC volts.

With a DMM sitting on a table, not connected to any circuit, you might
notice that if you only hold a single meter lead tip with your fingers,
that
the reading jumps around.

A quick check for the relative quality of a DMM is to set it on the
lowest
voltage range with no leads attached. The display should be zero or a
very
low reading that doesn't fluctuate. Fluctuation can indicate that there
is
no shielding, or that it's inadequate, and some low-end meters are the
worst.

Depending upon the design of the DMM meter's input and conversion
circuitry,
the readings can be very unreliable, especially when checking for AC
voltages.

Generally, the only analog AC meters that will give unusual-looking
readings, are the amplified ones that are intended to measure very small
potentials in the micro or millivolt potentials (not for AC
house/building
wiring troubleshooting).

WB
..............




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