How to use a multimeter

[ldvorak]

Just bought a multimeter and would like suggestions on good book for beginner use. Thank you

[gbaglo]

I think you'll find all you need on Youtube.

[ldvorak]

Just looking at some of the videos on YouTube. You are correct. Thank you!

[Wunfiddy]

Your multimeter measures voltage potential. Touch your meter leads to two points on a live wire, and it will show 0 volts. Touch one lead to the live wire and one to ground (or neutral in an AC circuit) and it will show the voltage present.
A good quality meter is your friend. One that can do Ohms, Volts AC and DC, Amps, and capacitance is a good investment.

[gbaglo]

if you use it infrequently, make sure you keep the instruction booklet and remove the battery when not in use for a prolonged time.

[John in Santa Cruz]

a few tips.....

NEVER use OHMS mode on a powered circuit, only to test devices that are disconnected from any power source.

NEVER connect a meter in MA or AMPS mode across a voltage source, only use amps mode in SERIES with a load.

ALWAYS put the meter back in VOLT mode as soon as you are done using OHM or AMPS/mA.

[alanmalk]

Originally Posted by John in Santa Cruz

a few tips.....

And if you are like me, ALWAYS have a few spare fuses for the meter.

[John in Santa Cruz]

yeah, there's typically two fuses, one for the "10 A" mode that uses a separate input, and another for the milliamp modes, both are fast-blow. Fluke meters use an odd size fuse for that 10A thing, but when I went to the counter of a local electrical wholesaler (who also sells retail), they knew exactly what I wanted and had a little bin of them.

[ldvorak]

Thanks to all who made suggestions to my thread. I really appreciate it. I will try to find replacement fuses now....

[AllanEdie]

Got mine from Amazon, both the 10 amp ones, and the milliamp ones. The sizes seem to be standard for many units, but you should check the dimensions of yours before ordering. The sizes are often mentioned in the Amazon listings.

[Vermilye]

Since you already bought it, this is a bit late, but for your next one consider a version that is a clamp on DC amp meter. Most clamp on meters only measure AC current, but there are versions that can measure DC. Much easier than opening the circuit to insert an amp meter in series with the load.

The Amprobe is a good one, but there are less expensive ones available.

[alanmalk]

Originally Posted by Vermilye

Since you already bought it, this is a bit late, but for your next one consider a version that is a clamp on DC amp meter.
...

The Amprobe is a good one, but there are less expensive ones available.

Jon, I am having a hard time seeing the specifications that would confirm a DC current range - for the particular meter you linked.

[Centex]

Originally Posted by Vermilye

Since you already bought it, this is a bit late, but for your next one consider a version that is a clamp on DC amp meter. Most clamp on meters only measure AC current, but there are versions that can measure DC. Much easier than opening the circuit to insert an amp meter in series with the load.

The Amprobe is a good one, but there are less expensive ones available.

Please take care if looking for a clamp meter capable of measuring DC AMPS - the linked-above Amprobe ACD-6 Pro does NOT provide that function (see Amprobe datasheet here).

The Fluke 325 listed here does, perhaps Amprobe offers a different model at a lower cost than the Fluke which does, too?

Yep, DC amps with a clamp meter is definitely handy.

[Vermilye]

Originally Posted by alanmalk

Jon, I am having a hard time seeing the specifications that would confirm a DC current range - for the particular meter you linked.

You are correct - that is what happens when I depend on a search on Amazon. Sorry for the misinformation.

Here is one that does claim to do DC with the jaws. Note that the maximum current is only 100 amps - not enough if you want to measure inverter input for large loads...

I have an Amprobe AC/DC 3000 which is discontinued & replaced by the Amprobe ACDC-3400 IND, but at $350.00 is way too much for the typical RV owner.

[Brian B-P]

Originally Posted by gbaglo

I think you'll find all you need on Youtube.

I think you'll find that most of it is intolerably long or just stupid, and some is blatantly wrong... because it's on YouTube.

[Brian B-P]

Originally Posted by Wunfiddy

Your multimeter measures voltage potential. Touch your meter leads to two points on a live wire, and it will show 0 volts. Touch one lead to the live wire and one to ground (or neutral in an AC circuit) and it will show the voltage present.

Well, that's a voltmeter. Try using your multimeter as a voltmeter - especially on 120 volts - when the switch is in an ammeter position and bad things can happen.

Originally Posted by Wunfiddy

A good quality meter is your friend. One that can do Ohms, Volts AC and DC, Amps, and capacitance is a good investment.

Yes... and the manual which shows you how to use it is your friend, too.

[Centex]

Originally Posted by Vermilye

...I have an Amprobe AC/DC 3000 which is discontinued & replaced by the Amprobe ACDC-3400 IND, but at $350.00 is way too much for the typical RV owner.

Bingo!

Yeah, one pays dearly for higher ranges of capability (ability to measure higher DC amps) so it can pay to think about what one really needs, carefully read the meter range specs, and shop accordingly

[John in Santa Cruz]

my retired EE friend calls those DC clamp-on's "Amp guessers". they aren't very accurate and quite a few things can throw them way off. but OTOH, often as not, you just want to know the approximate amount of current, and whether its 5 amps or 7 amps isn't that big of a deal.

[Hawkeye Ed]

Originally Posted by ldvorak

Just bought a multimeter and would like suggestions on good book for beginner use. Thank you

I like the explanations on the SparkFun web site:

https://learn.sparkfun.com/tutorials...multimeter/all