Uses for a multimeter

[hubner]

Apart from checking batteries, would the average person have other uses for a multimeter?

[Kim]

Testing continuity (for cables, connections, fuses, etc) is the other big one.  You want a meter that beeps in continuity mode, so you can look at the dodgy connection you're wiggling rather than the display while you're doing it.

[Feanor]

Basic fault-finding electrical problems...

Is there any voltage getting to this thing or not?
How far is the voltage getting?

Checking fuses
Checking the resistance of light bulbs or heating elements to see if they are dead

Trying to discover which wires are which when you have removed a light switch / light fitting without paying attention to where all the wires went...

[Canardly]

The last time I used one allowed me to quickly diagnose a lighting fault via a 9 pin trailer coupling by checking continuity to the pins.

[ScumOfTheRoad]

Actually, if you are talking about dry cell batteries don't bother with a multimeter. Get a cheap battery meter from Amazon. This one is fantastic:

https://www.amazon.co.uk/gp/product/B07TB81DHT/
Tests good/medium/poor for a whole range of cylindrical and button cells.

Dont want to appear snotty but I have taught physics labs at university level including how to use Avo meters - real old school multimeters.

[hubner]

There's one at Lidl at the moment for £13.

[Kim]

Actually, if you are talking about dry cell batteries don't bother with a multimeter. Get a cheap battery meter from Amazon.

This is a valid point.  A multimeter's voltage range measures voltage, while drawing as little current from whatever you're probing as is practical.  This is usually what you want for diagnosing circuits, taking measurements etc.

But the main electrical change that batteries undergo as they discharge isn't so much that their voltage drops, as their internal resistance increases.  A partially discharged battery that's been sitting around for a while may give a nice high voltage when measured with a voltmeter, but this drops as soon as it's put under load and some of that voltage is lost to overcoming the internal resistance.

Cheap battery meters incorporate a resistor that puts a load on the battery while measuring its voltage.  This gives a much better indication of the battery's state of charge.

Some multimeters might incorporate a battery testing mode that does this, but it's not a normal feature.

[Diver300]

Actually, if you are talking about dry cell batteries don't bother with a multimeter. Get a cheap battery meter from Amazon.

This is a valid point.  A multimeter's voltage range measures voltage, while drawing as little current from whatever you're probing as is practical.  This is usually what you want for diagnosing circuits, taking measurements etc.

But the main electrical change that batteries undergo as they discharge isn't so much that their voltage drops, as their internal resistance increases.  A partially discharged battery that's been sitting around for a while may give a nice high voltage when measured with a voltmeter, but this drops as soon as it's put under load and some of that voltage is lost to overcoming the internal resistance.

Cheap battery meters incorporate a resistor that puts a load on the battery while measuring its voltage.  This gives a much better indication of the battery's state of charge.

Some multimeters might incorporate a battery testing mode that does this, but it's not a normal feature.

Alkaline batteries are somewhat of an exception to this. Their no-load voltage does change from around 1.6 V when new to 1.2 V when flat. Of course some devices are much, much better than others at using batteries until they are really flat, so battery state isn't a good indication of whether the device will work.

Also, if you drop an alkaline battery, pointy end down, from about 2 cm onto a hard surface, it will bounce if flat. If new, it will just land with a thud. (Dead ones have bubbles in the electrolyte, which give the bounce.

[road-runner]

https://www.amazon.co.uk/gp/product/B07TB81DHT/
Tests good/medium/poor for a whole range of cylindrical and button cells.

That one only tests alkaline batteries. This one, also by Dlyfull, will test alkaline or rechargeables (Ni-MH, Ni-CD, Li-ion & LiFe04).

[rr]

Actually, if you are talking about dry cell batteries don't bother with a multimeter. Get a cheap battery meter from Amazon.

This is a valid point.  A multimeter's voltage range measures voltage, while drawing as little current from whatever you're probing as is practical.  This is usually what you want for diagnosing circuits, taking measurements etc.

But the main electrical change that batteries undergo as they discharge isn't so much that their voltage drops, as their internal resistance increases.  A partially discharged battery that's been sitting around for a while may give a nice high voltage when measured with a voltmeter, but this drops as soon as it's put under load and some of that voltage is lost to overcoming the internal resistance.

Cheap battery meters incorporate a resistor that puts a load on the battery while measuring its voltage.  This gives a much better indication of the battery's state of charge.

Some multimeters might incorporate a battery testing mode that does this, but it's not a normal feature.

Alkaline batteries are somewhat of an exception to this. Their no-load voltage does change from around 1.6 V when new to 1.2 V when flat. Of course some devices are much, much better than others at using batteries until they are really flat, so battery state isn't a good indication of whether the device will work.

Also, if you drop an alkaline battery, pointy end down, from about 2 cm onto a hard surface, it will bounce if flat. If new, it will just land with a thud. (Dead ones have bubbles in the electrolyte, which give the bounce.

I have a 4.7kΩ resistor with clips.on each end to attach to my probes for testing batteries.

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