digital ammeter with 'centre zero'.

[T i m]

<snip>

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

[Paul]

I found one that's pretty weird. It almost looks like it's autoranging, so you can get an extra digit after the decimal point. The pictures don't tell you here, what's in the box.

The Amazon version shows a box which might be a "transmitter". The second box with display is the "receiver". Range suggests it might be Bluetooth (lowest class). It uses a Hall Probe. It has a sign bit, that shows in some pictures and not others in the imall picture set.

It's quite a tease, and you might end up buying it from Aliexpress.

Like most of these products, totally untraceable, can't get a manual. And based on other product purchases of this type, the documentation in the box is the "single sheet, good luck" kind.

I've been trying to find someone to vend just the Hall Probe part, in the hope of finding a lower-amps one. These things *do* work at lower currents, because the first one I ever worked on, at work, was at lower currents. That was a long time ago for that project. Even back then, you could see the stuff drift a bit with time. I was making a PCB for student lab usage (a lab about Hall Probes).

Paul