Tips on DMM for a newbie?

"Rui Maciel"

** DMMs use probes - not tips.

Fuckwit.

... Phil

If it's the "on-off switch" type and not the "rotate to turn on and select the function" type then get into the habit of leaving the DMM set to a moderately high voltage range when you're finished with it.

That prevents those unfortunate learning experiences when one picks up the DMM for the first time in a month intending to measure a voltage source -- but it was left in an amperage range and blows the fuse (if you're lucky) or the meter (if you're not).

--
Rich Webb     Norfolk, VA

Buy a cheap one, and start using it. You'll then learn from experience what is there, and get a better idea of what you might want in the way of a better DMM. Someone already pointed out the need to be careful or you'll wreck the meter, a beginner is far more likely to make mistakes than one with experience, so buying a cheap meter means you won't lose much if/when you do damage the meter. Or your interest in electronics won't last, so you haven't spent too much on it by buying the cheap meter.

People could supply a list of "needed test equipment", but you have to be the judge of what you need and can afford, but you won't get to that point until you've actually started doing things. So when you can, it is far better to start with used or cheap equipment, to get a feel for it, which helps you to make an informed decision when/if you need something better.

I bought my first oscilliscope at an amateur radio auction for five dollars, it was horrible, heavy and very old almost forty years ago, but it gave me something to play with, which at that point was mostly what I wanted a scope for. I learned the basics, and then learned how lousy that scope was. That seems to be a better situation than being told what you need, spending the money, and then not knowing what to do with the scope.

Michael

Good point. Yet, there are tons of cheap portable DMMs on ebay which, besides external appearance and what sort of battery they take, appear to lack any relevant difference. Are there any features that I should look for?

Thanks for the tip, Michael. You do make a good point.

Thanks for the help, Rui Maciel

external appearance

Are there any features

A backlight for the display is nice to have.

A "true RMS" meter may be useful on the AC ranges. On the other hand, the non-"true RMS" meters are set internally to convert average to RMS for sine wave inputs so, as long as what you're measuring is pretty close to a sine shape, the results should be close enough for most purposes. If you really need a 0.1% or better RMS value for odd-shaped waveforms, you'd probably already know.

Pick up a set of inexpensive banana to mini-clip (or alligator) test leads. That lets you clip the DMM to the circuit's ground reference and frees up one hand to do something else, or to clip one to ground and one to a test point to leave both hands free while you adjust the gizmo.

--
Rich Webb     Norfolk, VA

Check the position of your probes every time. Many meters have no fuse in the 20 Amp. position and trying to measure line in this condition will be dangerous.

Tom

Jesus Phil, is our language that hard to comprehend or you guys down under just don't get it?

P.S.

This should start a fire ball of two!

:)

Jamie

Go to a harborfreight store, if you have one near by or order on line..

They have some that will be fine for first timers..

Until I got to the 'F...wit' part, I thought he actually made a joke. Nice to know of some constants in the universe.

G=B2

here's a few tips

if the meter has a current range, it will act like a short circuit across the probes. The meter will either blow a fuse or just burn out if you set it to say a 250mA range and connect it to a large battery or an outlet.

In the volts range, it's much harder to break the meter

measuting the currents and voltages in a flashlight is usually pretty easy and will let you learn what the meter is doing without breaking anything.

When a DMM acts weird, it may be time for new batteries, even if you think they are still good.

if the meter has a diode check or continuity mode, it can usually run a LED, at least if it's a red one.

measure whatever you can, like the output of power supplies that plug into the wall or stuff like that. The more you do something, the more familiar it becomes and the more sense it makes in the end.

Electronics is a hands-on activity.

ah Phil, sounds like you got up on the right side of the bed. Mike

** Nope.

But the f****it OP needs to learn how to post a meaningful question.

Cos what he just post is not one.

.... Phil

Or fell through the broken seat in the outhouse.

--
Anyone wanting to run for any political office in the US should have to
have a DD214, and a honorable discharge.

Sigh. Can't you read? He's in SA, not the US. Shipping costs and import duty would wipe out any savings ordering one from HF.

--
Anyone wanting to run for any political office in the US should have to
have a DD214, and a honorable discharge.

Definitely agree with the above.

Don't buy from ebay.

These guys (below) sell to a lot of engineers, technicians and hobbyists. They seem to be reliable.

This is a good choice for a first multimeter if you are a careful double checking sort of person.

This is about as cheap a meter as I would suggest for a first meter.

There is also a similarly named company called

They have a wider range of hobbyist level tools at slightly lower prices. They are also reliable.

Two other points - buy an energy authority approved soldering iron from a supplier in your own country - not from ebay or from overseas - and if your house is not fitted with earth leakage detection get yourself a portable unit for use with your gear.

Last, throw away any supplied batteries and fit good quality alkaline like Eveready or Duracell - its not so much for the long life but to make sure it doesn't leak and wreck your meter (for the $15 meter it probably doesn't mater)

Indeed. Ebay does have quite a lot of cheap DMMs but they are all chinese knock-offs. Cheap is good but I'm not very comfortable contributing to this sort of shenanigans.

Those sites do look good but. Unfortunately, as they are chinese companies it is very possible that, if I order stuff from them, the customs people would create all sorts of problems. Are there any decent sites that sell stuff from within europe?

Thanks for the tips, David.

Rui Maciel

knock-offs. Cheap is

is very possible

problems. Are there

Many countries have a minimum amount of customs to collect - if you are under that amount they don't care (it costs more to collect than it is worth) also tools are often tax free or at least tax reduced. Check with the appropriate department, it will at least be worth your time.

I can't help you with Europe specific info. Someone on this newsgroup mentioned a german company called Conrad.

Harbor Freight - 7 function - DMM - $1.99

Only problem is using it in direct sunlight which adds about 0.5 to the reading. Use in shaded light only.

-Bill

those things are sold and have been sold in a variety of inners with all kinds of different names on them...

I still have some older ones I got that allows you to tie the common of the bat to the common input. Makes for a quick hack display.. Most of the ones they have now won't let you do that, even though they look the same on the out side. Different board.

I think I paid like $3.00 each from a tool flea market. I got a arm full that day... They make good wheel wedges and don't hurt so much when they fail!