Another multimeter thread

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I need a voltmeter that can go 4 places to the RIGHT of the decimal minimum.
I am working with a 0-2.5 volt differential input 16 bit A/D converter and my 3 1/3 meter is obviously not going to cut it.

I am going to hit up EBAY right now, but if anyone has a unit in mind I would appreciate some feedback.

If anyone has one they want to sell, rent, or loan me PM me.

Thanks in advance.

I would rather attempt something great and fail, than attempt nothing and succeed - Fortune Cookie

 

"The critical shortage here is not stuff, but time." - Johan Ekdahl

 

"Step N is required before you can do step N+1!" - ka7ehk

 

"If you want a career with a known path - become an undertaker. Dead people don't sue!" - Kartman

"Why is there a "Highway to Hell" and only a "Stairway to Heaven"? A prediction of the expected traffic load?"  - Lee "theusch"

 

Speak sweetly. It makes your words easier to digest when at a later date you have to eat them ;-)  - Source Unknown

Please Read: Code-of-Conduct

Atmel Studio6.2/AS7, DipTrace, Quartus, MPLAB, RSLogix user

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jgmdesign wrote:
I need a voltmeter that can go 4 places to the RIGHT of the decimal minimum.

That would be a resolution of 0.1mV for last digit ?

I am using an Amprobe 37XR-A, it has that resolution plus a decent number of other functions.

Peter

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Thanks Peter.

Thats a nice meter for the price. my only hit on it is that it goes from 1.0v then 10.0v with no intermediate but thats ok, I can live with it.

I would rather attempt something great and fail, than attempt nothing and succeed - Fortune Cookie

 

"The critical shortage here is not stuff, but time." - Johan Ekdahl

 

"Step N is required before you can do step N+1!" - ka7ehk

 

"If you want a career with a known path - become an undertaker. Dead people don't sue!" - Kartman

"Why is there a "Highway to Hell" and only a "Stairway to Heaven"? A prediction of the expected traffic load?"  - Lee "theusch"

 

Speak sweetly. It makes your words easier to digest when at a later date you have to eat them ;-)  - Source Unknown

Please Read: Code-of-Conduct

Atmel Studio6.2/AS7, DipTrace, Quartus, MPLAB, RSLogix user

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peteralarsen wrote:
jgmdesign wrote:
I need a voltmeter that can go 4 places to the RIGHT of the decimal minimum.

That would be a resolution of 0.1mV for last digit ?

I am using an Amprobe 37XR-A, it has that resolution plus a decent number of other functions.

Peter

Some of mine Peter. I really like it. We use it only for electronics, below 50 V.
I bought it on 2010.

Regards,

Bruno Muswieck

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Quote:
my only hit on it is that it goes from 1.0v then 10.0v with no intermediate but thats ok, I can live with it.

With 0-2.5V measurement range you have to set a +-10V range on that Meterman. It has a 0.1% base accuracy (which means the readout is within +-10mV at that range) and resolution of 1mV.
Now, if you pick the el-cheapo +-1999 multimeter for under 5$ (those have a 0.5% base accuracy on a voltage range) and set it to +-2V range then you get same accuracy and same resolution as with Meterman but for the fraction of the price. Of course you cannot cover 0-2.5V range with +-2V multimeter but offsetting a voltage by half a range can be made very accurate for pennies.

No RSTDISBL, no fun!

Last Edited: Sun. Oct 20, 2013 - 03:31 PM
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Jim,

I've got a Fluke 8845, 6-1/2 digit bench-top meter I'd be willing to let go.

The meter only has about 10 hours of on-time. I purchased the Fluke 8845 for a project because I was working on a project where we had to know the sleep current of a the ATmega324 that I was using on a consulting gig I was doing.

The project ended abruptly because the client passed before the project was completed. Another project where money was spent, with all loss and no return.

This meter might be out of your price range but, I'd let the Fluke 8845 go for $700.00 + shipping. The meter - new - runs at $1,000.00 at various outlets.

You can avoid reality, for a while.  But you can't avoid the consequences of reality! - C.W. Livingston

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Great ideas all!

Carl,
If I had the $$ you would have a PM for Paypal right now.

So far the Amprobe looks good. Great to throw in my backpack for a field trip.

I am still exploring ebay as well but not very hard.

I would rather attempt something great and fail, than attempt nothing and succeed - Fortune Cookie

 

"The critical shortage here is not stuff, but time." - Johan Ekdahl

 

"Step N is required before you can do step N+1!" - ka7ehk

 

"If you want a career with a known path - become an undertaker. Dead people don't sue!" - Kartman

"Why is there a "Highway to Hell" and only a "Stairway to Heaven"? A prediction of the expected traffic load?"  - Lee "theusch"

 

Speak sweetly. It makes your words easier to digest when at a later date you have to eat them ;-)  - Source Unknown

Please Read: Code-of-Conduct

Atmel Studio6.2/AS7, DipTrace, Quartus, MPLAB, RSLogix user

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jgmdesign wrote:
Great ideas all!

Carl,
If I had the $$ you would have a PM for Paypal right now.

So far the Amprobe looks good. Great to throw in my backpack for a field trip.

I am still exploring ebay as well but not very hard.


I understand.

I'm glad you didn't just deposit any money into Pay-Pal.

Zbaird deposited some money into my Pay-Pal account several years ago, as have others. To date, I have about $400.00 in Pay-Pal that I've never been able to gain access to because someone hacked my account and Pay-Pal doesn't seem too interested in dealing with the problem.

Needless to say, I prefer to remain as far away from having anything to do with Pay-Pal.

Anyway, I thought I'd make the offer as, I haven't ever used the meter since the project came to a tragic end.

You can avoid reality, for a while.  But you can't avoid the consequences of reality! - C.W. Livingston

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If a bench meter is ok ... (You mention backpack)
I recently got a Keithley 2015THD 6.5 digit meter from this guy (in UK) , ebay #251352516728
His shipping isn't accurate , i only payed £20 with UPS to DK.

Mine came with a May-2011 cal certificate sticker on it ....
Not bad ....

But we're getting close to Carl's price.

The THD (audio) part of the meter is supposed to be quite usefull (for some) .... :oops:

I was told by keithley, that it's a 2000 measurement engine, with the extra THD board added.

Edit:
Ohh - A HP-3478A is a 5.5 digit bench meter , usually around $100..$200 on *Bay

Unless you know someone at a Cal-Lab , don't get one that shows Uncal during startup ... Like this one says *bay # 380738587055. The Cal-would prob cost the same (or more) than/as the meter.

If you can fix the powerbutton on this one (seems to be just the plastic cap) , then this one might be good *Bay #261311525080

It has the Cal-Sticker in front and on back intact.

/Bingo

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Fluke 8800A 5.5 digit meters are pretty cheap on Ebay, like this one:

[url]
http://www.ebay.com/itm/Fluke-88...
[/url]

Tom Pappano
Tulsa, Oklahoma

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I remember the old 8800. Good unit.

I would rather attempt something great and fail, than attempt nothing and succeed - Fortune Cookie

 

"The critical shortage here is not stuff, but time." - Johan Ekdahl

 

"Step N is required before you can do step N+1!" - ka7ehk

 

"If you want a career with a known path - become an undertaker. Dead people don't sue!" - Kartman

"Why is there a "Highway to Hell" and only a "Stairway to Heaven"? A prediction of the expected traffic load?"  - Lee "theusch"

 

Speak sweetly. It makes your words easier to digest when at a later date you have to eat them ;-)  - Source Unknown

Please Read: Code-of-Conduct

Atmel Studio6.2/AS7, DipTrace, Quartus, MPLAB, RSLogix user

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My everyday meter on my bench is the *8400*, Nixie tubes and all! Built in 1969, I think!

Tom Pappano
Tulsa, Oklahoma

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I bought a new Fluke 8842A in 87 and a used one with a gpib option in about 98 for less than the cost of the gpib add on module. Both still work fine.

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Brutte wrote:
Quote:
Of course you cannot cover 0-2.5V range with +-2V multimeter but offsetting a voltage by half a range can be made very accurate for pennies.

Can you elaborate on what technique that would be?

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Quote:
Can you elaborate on what technique that would be?

How to divide a voltage in half??
A simplest version is with a regular voltage divider with matched resistors. Pick a bunch of those (metal-film 1% are great), any reasonable nominal value, and pick a pair that has same voltages (U-U/2)==(U/2-0) under some steady current when connected in series. The idea is that nominal values (of current, resistances or voltages) are not important in here so the error of a match can be made close to within the resolution (not the accuracy) of the voltmeter used for matching. That is, for an el-cheapo, the matching error is below 500ppm.

Now, if you apply one end of a DMM to the (possibly buffered) U/2 then you can cover whole range of the [0V:+2.5V] measurement inside the [-2V:+2V] range.
lxcmk

No RSTDISBL, no fun!