Managed to resist the (naked) battery SDS at Lidl for £60. They had some batteries and single and double chargers. Bought a digital clamp meter for £13. Only AC amps (to 600) but has separate leads for AC and DC volts, continuity/diode, ohms and (unusually) capacitance and Hz. Nice fast, stable 4 digit display.
Aldi had assorted diamond disks for angle grinder, and also the angled flap type abrasive disks for 125mm angle grinder
Ta.
Bought the clamp meter for £12.99 at our local Lidl. Described as pliers amp meter 0346215.
Haven't had a play with it yet.
Cheers
Dave R
DC clamp meters tend to be rather expensive and none too accurate, sadly. At lowish currents, anyway. Would be very useful on a car to get an easy accurate measurement of a small(ish) current.
A link would be useful as I have no idea what you are talking about
Go to the Lidl site and look for the 'middle of Lidl' offers. As they may not be exactly the same everywhere in the country. And if in demand, can sell out very quickly.
I didn't see the clamp meter on the Lidl website - they don't appear to have a DIY event on. There's one a week Sunday, but no clamp meter there either.
Theo
As Dave says you get regional variations. The web sites are *sometimes* useful to provide advanced notice, for example when I wanted more 20V batteries these showed that more naked tools were in in four weeks or so (and they usually have batteries when they are selling naked tools). I have a very local Lidl so I tend to drop in on Thursdays. The Aldis are more remote so I sometimes drop in when passing.
They can use Hall Probes.
Magnetic field goes in one axis.
Constant current is pumped along a second axis.
The third axis develops a voltage, which can be buffered with an opamp before being measured with a dual slope converter (for cheapness). It follows the Right Hand Rule you're taught in physics. On a clamp on ammeter, they've already arranged the jaws to feed the Z-axis for you. Magic.
Hall Probes aren't particularly sensitive. A lab-grade electrometer can measure currents below a picoampere. The clamp-on DC ammeter is probably 12 orders of magnitude less sensitive.
Where the DC ammeters excel, is measuring heavy currents without heating effects. When I wanted to check the starter on my car, the peak hold on the DC clamp meter could tell me the max current was 150 amps. And nothing in the measurement kit gets warm while doing so. A conventional multimeter, has in small print to "not be measuring 20 amp loads without allowing sufficient cooling time (duty cycle)". A DC clamp meter has no such limit. It can measure a heavy current, for as long as the nine volt battery in the meter lasts.
There is some drift in the offset voltage of the Hall Probe and buffer amp. That's why typical DC clamp meters have a "Zero button" on them. Part of the zeroing problem could be attributed to the magnitude of current run through the semiconductor detector. The one I set up for physics lab, we were using 250mA for that, which is a lot more than a hand-held clamp meter uses. And that's going to cause some die heating (resistive loss). But since the sensitivity, it's a multiplier, and multiplies the constant current times the mag field, the higher the current, the more output voltage. Then, if your stupid move caused a big-assed drift, that's your fault :-) The clamp-on ammeter has some different tradeoffs to consider. And battery life precludes using large constant current values. The battery budget might only have 1mA for the sensor to use, and
6mA for the meter chip.Paul
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