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View Full Version : What Leads For A Digital Multimeter?



abrogard
12-14-2007, 03:49 PM
I just got a digital multimeter, the first one I've ever owned or touched, for only $10, new!

Great stuff. But it came without leads. And when I look at it I see not two holes marked + and - as with my old analog meter, but three, with strange markings.

So I don't know what to put in where.

Could someone please help me? I've attached a pic.

regards,

ab :)

BrianJohn
12-14-2007, 04:03 PM
Common and the hole right above common, the bottom two holes, third hole upper most is for measuring amperage utilizing the meter in series with the load and source.

I thought when you said you paid $10.00 for it that it came without holes.

jimbo
12-14-2007, 04:34 PM
Make sure not to connect the meter ACROSS a voltage source with the COM and 10AMP leads, as that is pretty much a dead short.

The blue socket on the left is to connect the three leads of a transistor ( 2 types, NPN and PNP)

HandyAndy
12-14-2007, 05:20 PM
Radio shack sold meter leads at one time, I think they still do,

abrogard
12-14-2007, 05:30 PM
Okay, got it. I use the bottom two holes. The bottom one is negative and the middle one is positive, to use my old analog meter terminology.

The 'COM' marking threw me. I didn't think of 'common' as an answer. And I still don't really understand it, but okay, earth, neg, like that.

DON'T use the 10ADC and COM across a voltage source. Those two are to be used in series when measuring amperage with a hefty 10Amp maximum. Well, sounds hefty to me. I've never ever before measured current but I guess I'll be bound to have a go now I've got an instrument.

Thanks for the help, guys.

I actually googled it and found it well represented. Available in the States at a recommended retail of $us15 !

Sold by another outfit with 1 year's warrantee!

Pity it doesn't come with a manual.

I'll go get some leads for it and play with it...

regards,

ab :)

480sparky
12-14-2007, 05:50 PM
Infortunately, the on-line instructions (http://www.projecta.com.au/documents/item/309) aren't much help.

abrogard
12-14-2007, 10:53 PM
Actually it turns out I've been too hasty once again... under the cardboard backplate of the blister pack was a kinda long bubble going across the bottom, something like you get on blister packs of screws, so's the vendors can stand 'em up on display I guess.

But this wasn't for standing up for display, it had a little instruction booklet and a pair of leads in it!

All for $10. Ah, it's a lovely time for penurious home handymen (if it weren't for the cost of timber and steel, that is, but you can't have everything).

But thanks for the link to those other instructions, they're more comprehensive than the stuff I got, I've downloaded them and I'd read up on 'em.

regards,

ab :)

hj
12-15-2007, 06:43 AM
Personally, any multimeter without a snap around ammeter is almost worthless to me.

speedbump
12-15-2007, 06:50 AM
Personally, any multimeter without a snap around ammeter is almost worthless to me.

Snap around's are a lot safer too, they don't flash and hurt your eyes when you wrap them around a load larger than they can handle.

bob...

BrianJohn
12-15-2007, 06:59 AM
Snap around's are a lot safer too, they don't flash and hurt your eyes when you wrap them around a load larger than they can handle.


?????? Could you expand on this.

I own a variety of clamp-on amp meters and have NEVER seen a flash.

As for a clamp-on amp meter having additional functions, that is user specific. I never use a clamp-on for anything but measuring current.

speedbump
12-15-2007, 07:17 AM
Make sure not to connect the meter ACROSS a voltage source with the COM and 10AMP leads, as that is pretty much a dead short.This is the reason. If you were to use the amp and common leads to try and measure voltage on a 115 volt outlet, you would probably see the flash. Snap on current meters don't physically touch the voltage like the leads do.

bob...

Bob NH
12-15-2007, 07:44 AM
I think it is confusing to suggest that a snap-on (sometimes called clamp-on) ammeter is required. The only function that a snap-on ammeter has that a standard multimeter does not have is the ability to measure Alternating Current (A/C). That is essential in some cases but is probably less than 1% of the applications for a typical homeowner.

It is rare that a homeowner would want to measure A/C current and I think using a multimeter for that purpose on 120 Volt circuits is probably hazardous. The only time I try to measure current with mine is small DC circuits.

I have both and prefer the multimeter for most things because it has more ranges and a better display.

Also a consideration for the typical homeowner is that you can get a multimeter for $10 and a decent snap-on ammeter costs $70 t0 $100 or more.

Every homeowner should own a multimeter and learn how to use it. It is good for checking lightbulbs, Christmas tree light strings, batterys, cords, and numerous other things.

Wet_Boots
12-15-2007, 09:15 AM
I just got a digital multimeter, the first one I've ever owned or touched, for only $10, new!

Great stuff. But it came without leads. And when I look at it I see not two holes marked + and - as with my old analog meter, but three, with strange markings.

So I don't know what to put in where.

Could someone please help me? I've attached a pic.

regards,

ab :)"banana plugs" are what will fit in the test meter connections. Pretty much standard issue for test leads.

BrianJohn
12-15-2007, 10:20 AM
A few thoughts on a DIYer and his inexpensive test equipment. The least expensive voltage tester most electricians utilize cost in the range of 35-60 dollars, and while this unit may be safe to use take care.

Be careful using this tester, always test this and any voltage tester for that matter on a known live circuit prior to use.

abrogard
12-15-2007, 11:59 AM
Yep, guys thanks for the input. I well understand the warning about checking the meter before use and the reminder is very good to have - my old radio shack analog meter had such puny wiring inside the leads that they just broke during the course of normal use and led me to detect no voltage on a circuit that was actually live.

My fault for not doing a resistance test first I guess. No matter who's fault - a very dangerous circumstance.

And thanks for the warnings about the 'flash that hurts the eyes', I got a laugh out of that but its equally serious I guess. My instructions read to let 15minutes go between current reading and not to leave it in circuit for longer than 10 seconds.

I guess I could get an eye hurting flash if I ignored those instructions on sufficiently beefy circuit.

I think I won't be using the ammeter part at all - I can't see where it would be useful when I'm constrained to one measurement every 15 minutes.

But I'm very satisfied with what I've got especially considering the price. A better replacement for the analog meter plus the transister checker is nice (even if I'm only playing) and it operates as a signal generator, too, it says, that'll be good, something else to explore.

I test wall plugs, light sockets, computer wiring, car wiring, that's it.

And I nearly got zapped that time with the broken lead on the analog, so I'm a bit wary. Not wary enough, though, that was a timely reminder. Thanks.

regards,

ab :)

hj
12-15-2007, 02:16 PM
when you get to the "checking electric water heater" part, then you will realize the benefit of a snap around ammeter.

480sparky
12-15-2007, 02:30 PM
A few thoughts on a DIYer and his inexpensive test equipment. The least expensive voltage tester most electricians utilize cost in the range of 35-60 dollars, and while this unit may be safe to use take care.

Be careful using this tester, always test this and any voltage tester for that matter on a known live circuit prior to use.

Otherwise, this (http://www.youtube.com/watch?v=i9jpwGTy66g&feature=related) might happen.:eek:

speedbump
12-17-2007, 06:35 AM
Ah rite Sparky, that's the flash I was talking about!

bob...

BrianJohn
12-17-2007, 10:00 AM
If you see a flash like that from using a multimeter on a voltage system with in the meters rating you have a good case for a lawsuit...

sbrn33
12-18-2007, 06:35 AM
If you see a flash like that from using a multimeter on a voltage system with in the meters rating you have a good case for a lawsuit...

I was thinking the same thing. Who hasn't had the leads in the wrong holes or the meter set on the wrong setting?
My lead set cost almost $30 bucks(without the meter). I can say I might be just a little scared checking 480 with that meter.

speedbump
12-18-2007, 07:04 AM
I can say I might be just a little scared checking 480 with that meter.
Or you can buy those $90.00 leads for that $10.00 meter. The ones that are 30 feet long; and let you get way back from the meter. Then you can check the higher voltages.

bob...

BrianJohn
12-19-2007, 05:02 AM
Any multimeter I have utilized has the Amp feature protected with a fuse, to prevent injury and/or damage to the meter. Though have investigated 2 instances where an electrician used a multimeter on 5 KV, not enough fuse for this protection.

Bob NH
12-19-2007, 06:52 AM
I would stick a plastic pin in that 10 Amp hole on the meter in the picture because it is too easy to stick the lead in that hole and try to measure 120 Volts.

jimbo
12-19-2007, 07:11 AM
I can say I might be just a little scared checking 480 with that meter.

Since most of the folks on this forum are (mainly) plumbers, I would venture that most of us should not even be in the same room as 480!!! Much less trying to measure it!!!

I remember, back in '02 { the phrase " back in '02" originated long before there was a 2002 to look back at!!!) , as a twidget ( electronic tech) we were cavalier about measuring KV (DC). High voltage, but very low current power supplies, like for radar or whatever. Also, DC zaps you different than AC. But I remember the electricians on the boat had enourmous respect for the 440 distribution. They used to say that stuff will "come and get you" if you mess up.

abrogard
12-19-2007, 12:41 PM
That's a good idea about blocking off that hole. I'll do something like that.

I didn't realise this was primarily a plumbing forum - i found it googling for electricians, with my multimeter problem.

So now I've got a plumbing problem, surprise, surprise.... I'll start a new thread would be the thing to do I reckon.

Back to meters: After my experience of false readings from meters with insufficiently strong leads I am truly wary and worried. I wonder what's the sure way to know that your dealing with a dead circuit? Those 'light up' screwdrivers that many electricians seem to carry? A 'snap on ammeter' ?

I read those comments about it being rare for the homeowner to want to read AC current (and therefore having little need for a snapon ammeter) but in fact it is our mains AC current that we most frequently deal with.

Just putting in a light globe. Replacing a fuse. Trying to fix a power point that's hanging off the wall (my next job) - it is my 240Volt AC supply that I have to deal with.

A defective desk lamp - it's all very trivial looking, cheap to buy, all plastic, super lightweight, thin cord - but it is powered by 240V AC!

'Switch off at the mains' is good advice, yes, but not always possible for one reason or another. And in any case more information, more options, is good.

Carry two meters? Always check with each?

I remember seeing sparkies in the Army always rubbing two wires together to see if they got a spark. Sounds a bit savage..

regards,

ab