Question about my new Multimeter

[Category 5]

I finally got a nice Extech True RMS Multimeter. I have been using the Radio Shack folding pocket meter to check voltages and resistance up until now.

Here's the deal.

On the little $25 pocket multimeter, when I connect the two leads together on the resistance setting it reads 00.0 ohms. This seems right to me since there is obviously no resistance other than the leads themselves. It is as if the meter is calibrated to read the resistance between the leads, minus the resistance of the leads themselves.

The new meter, regardless of the lead pair I use, readys 00.1 - 00.4 ohms fluctuating when no resistance is present. I often use the resistance setting to test the integrity of solder joints, and a reading of 00.3 would make me want to go back and resolder the connection.

Is it normal for a true RMS meter to read a small amount of resistance when none is present, or is my meter bad?

Shane

 

[Scenaria]

the RS one wasnt nearly as accurate..

.3 ohms for your leads isnt unreasonable... you just happen to have a new meter thats more precise...

enjoy it and dont worry

 

[Marik]

.3 ohms for your leads isnt unreasonable... you just happen to have a new meter thats more precise...

I have a Fluke 87 III multimeter. When shorted it gives me 000.3-000.4 ohm reading. Switched to 4 1/2 digits gives me fluctuating between 00.28 to 00.31 ohm. I was curious and measured its leads on my GenRad 1650A bridge, and got 0.085 ohm for both of them in series.

Anyway, as Scenaria's said, I wouldn't worry about it, as any more or less good DMM tends to do that. If you need to measure very low resistance, then you need a bridge.

 

[CJ]

the cheaper meter might have had a "dummy zero" on it. this just makes anything close to zero read zero, so the customer gets that warm fuzzy feeling that everything is cool. this is meant for sub- cultures in society that don't know a lot of electronics, and who don't care, like electricians, the HVAC crowd, and, oh yes, ebay surfers!
:razz:

funny thing related to this physco-trickery thing, a firned of mine installed a huge heating and ac system in a officer building. everybody was fighting over the thermostat, trying to dial in their favorite settings, much to the chargrin of their office mates. so my friend just put up a bunch of fake thermostats around the main offenders and the problem was solved. they thought that they were actualling feeling what they dialed in!

 

[Marik]

[quote author="cjenrick"]the cheaper meter might have had a "dummy zero" on it. this just makes anything close to zero read zero, so the customer gets that warm fuzzy feeling that everything is cool[/quote]

:green: :green: :green: :green: :green:

 

[Steve Jones]

Multimeters aren't designed for really low Ohm work anyway, so I wouldn't trust any of them below .1 Ohms.

I guess the thermostat con is a bit like when you grab an EQ knob in an analog board and think you can hear a difference when you turn the pot, but then you notice you are adjusting the wrong channel.

 

[Category 5]

Thanks guys. I just wanted to know if there was a mis-calibration or something in case I needed to return the meter.

I guess all is good and I'll enjoy my new tool. I love that it has a stand to sit upright, a backlit screen, and a GIANT lcd screen. The pocket meter was driving me batty!

Shane

 

[Category 5]

How about capacitance measurements? This thing takes at least 10-15 seconds to show a reasonable reading.


Shane

 

[NewYorkDave]

So impatient :roll: If you keep complaining, I'm going to sentence you to travel back in time to the days of manual-nulling impedance bridges :razz:

Are you testing an electrolytic cap?

Don't forget, a cap needs time to charge up! :wink:

 

[Category 5]

[quote author="NewYorkDave"]So impatient :roll: If you keep complaining, I'm going to sentence you to travel back in time to the days of manual-nulling impedance bridges :razz:

Are you testing an electrolytic cap?

Don't forget, a cap needs time to charge up! :wink:[/quote]

:shock:

Yes, electrolytic. The cap is just charging up I am sure. Forgive my impatience...I am just trying to figure out my new toy. My wife is going nuts! I am getting a reading of 24.68 volts between her nipples! :razz:

 

[NewYorkDave]

Dude, if I had been drinking something a moment ago, it would have been all over my keyboard right now. That's classic!

Try connecting a scope next time. You won't BELIEVE the waveforms that come out of those things :grin:

 

[Scenaria]

with a little "tweaking" you might actually hit 25 volts...

 

[Marik]

[quote author="NewYorkDave"]Dude, if I had been drinking something a moment ago, it would have been all over my keyboard right now. That's classic!

Try connecting a scope next time. You won't BELIEVE the waveforms that come out of those things :grin:[/quote]

Ha :grin: :grin: :grin: ,

Hey Dave, just wondering if you ever tried to kinda measure waveform or something, between those milky things:

http://www.groupdiy.com/index.php?topic=359&start=0

I am sure any DMM, including Fluke, or scope would explode or at least go out of scale even thinking of getting close with probes to those things.
:green: :green: :green: :thumb: :thumb: :thumb:

 

[Marik]

[quote author="NewYorkDave"]So impatient :roll: If you keep complaining, I'm going to sentence you to travel back in time to the days of manual-nulling impedance bridges :razz: [/quote]

Do you mean there is another way of doing that? :sad: :wink:

 

[Category 5]

[quote author="NewYorkDave"]
Try connecting a scope next time. You won't BELIEVE the waveforms that come out of those things :grin:[/quote]

Did it... She's oscillating. Must be that time of the month. Sigh. :sad:

 

[tony dB]

my adjusting attempt to get a 25 voltsreadout resulted in a ferm slap on the right ear btw... :evil:

Don't push your luck too far, especially in hormonesensitive days of the month

No-one has a good schemo for a periodmeter? one that reads 3 days upfront should be fine :thumb:

 

[Guest]

[quote author="tony dB"]
No-one has a good schemo for a periodmeter? one that reads 3 days upfront should be fine :thumb:[/quote]
Do what I do.. if I get shouted at for longer and louder than normal..... guess what's coming...

 

[tony dB]

feel a bit like sticking a wet finger at 240V and see what happens...
must be a more scientific way of approach?

After 25 years i can predict within a 6 to 12 hourrange when the inevitable happens... :roll: