On Thu, 10 Sep 2020 14:04:40 +0100, "Dave Plowman (News)"
wrote:

snip

Huh!? Just about every digital meter I have ever come across works
'both ways', you just get a number (for +ve) or a number with a - sign
in front (for -ve).

That's what I thought. (I've never actually tried it out for current
with my little Sinometer from Maplin though.)

Just checked with mine - and you do get a minus sign when you reverse the
leads. Not something I was sure about, as apart from with a charging
system like on a car, not usually important.

I rely on it often when checking (specifically) for polarity on stuff
and make use of it when I cba to put the red lead on the +ve. ;-)

I would mentally 'note' that a battery was displaying -13.6(V) when
I'm only interested in the numbers.

It's not often you would regular read both +ve and -ve in a domestic
situation (other than when it's going at 50Hz g), unless you were
say testing a PC PSU (volts) or the current in and out a solar charged
battery.

I have a very nice multi chemistry, multi cell charger that I've got
doing some cycling of a 7.2V NiMh stick packs (RC Car type). It only
displays the current but prepends that with C or D, depending on what
part of the cycle it's on (not +/- etc).

3300mA packs, 1A charge (Delta peak), 10 min wait, 1A discharge (down
to 1V / cell), 10 min wait, charge etc. Currently on '2 Cycles'.

Cheers, T i m