Looking for a good multimeter guide

[tty5150]

That should not have happened, period. Even if he had the meter set to amps (thus acting like a short across the 220 line), it should have just blown an internal fuse. Maybe popped a sort of scary arc at the probe tips. But explode like that? No way. Something was seriously wrong with the meter.

It could be a cheap and/or non matched fuse. In low-line DMM there is no fuse on 10A line, in better ones there is fuse, usually 5x20mm or (better) AG3 size. In some circumstances those fuses can explode really nasty. Just take a look here
http://www.tequipment.net/FlukeFuses.html#8
Good Fluke fuses are bigger, rated up to 1000V (instead of 250V) and costs more than cheap DMM. And are really fast-acting.

So, if you want to use cheap DMM for high currents measurement take one with fuse and upgrade it with a better, fast-acting, ceramic high breaking capacity fuse. Just for your safety.

 

[Mr Happy]

But what happens if you try to measure 220 V AC on a DC mV setting? You need a sensitive voltage input to pick up the mV, yet at the same time the 220 V must not exceed any breakdown voltages. It seems to me that is a more severe test than trying to measure high voltages on a 10 A current setting where the fuse can protect it.

 

[TorchBoy]

(ALL MM's, even the most expensive, must be recalibrated occasionally to maintain their accuracy).

Let's keep our feet on the ground here. Not all of us are willing to shell out what a Fluke costs when we just want a meter for occasional hobby or home use. There are plenty of sub-$10 DMMs out there that measure voltage and current quite accurately enough for what we need them for.

Honestly Zenster, it's just my hobby, not my life. I really don't mind if my DMMs are a tad out.

 

[tty5150]

But what happens if you try to measure 220 V AC on a DC mV setting? You need a sensitive voltage input to pick up the mV, yet at the same time the 220 V must not exceed any breakdown voltages. It seems to me that is a more severe test than trying to measure high voltages on a 10 A current setting where the fuse can protect it.

I'm not an expert, but as far as I know it is a current measurement that could be some how dangerous. On autoranging DMM there is just one position for voltage. Meter will adjust to voltage level, from mV to usually 600V. And DC/AC measurement differs only in way to calculate it - in case of AC device has to calculate effective voltage. In both cases current flow via DMM is very low.

Current measurement is in fact kind of shortcut. If current is to high fuse should break the circuit, but rarely small fuses can explode.

Better meters have warning signal if probes are in Amps slots and dial is set to different position.

Here is some info:
Beware of Cheap Meters

When replacing fuses go with ceramic, voltage as high as possible, fast -action, high breaking capacity
[SIZE=+1]Fuse Facts[/SIZE]