What is Digital Multimeter Impedance?

Measure it with a DVM!

John

yes, you can also measure a supply through an xx meg resistor and do the math.

John

Reply to
John Larkin
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Unless your older analog meters had a FET input, the impedance wouldn't have been anywhere near that high -- more in the ballpark of 1k-100k, actually!

That Fluke Multimeter probably is about 10M, although it's likely to be spec'd as something like 10M in parallel with, say, 20pF, so by the time you hit

10kHz you'd be down to under 1M.

---Joel

Reply to
Joel Kolstad

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Download the user\'s manual from:

http://us.fluke.com/usen/support/manuals/default.htm
Reply to
John Fields

"Kevin Doyle" wrote in news:aPBBe.2499$ snipped-for-privacy@news.indigo.ie:

doesn't it say in the manual? Some DMMs are 22 Mohms.

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Jim Yanik
jyanik
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Reply to
Jim Yanik

Hi all I have a Fluke 12 DMM and was wondering what is a impedance of such a device. I know that the older analogue Multimeters would be in the range of 10 to

11M ohms.

Cheers, Kevin.

Reply to
Kevin Doyle

Oh thanks. I should have known that!!

Reply to
Kevin Doyle

Quite high. Have you checked the manufacturer's data ?

Analogue ? You mean moving coil ? Those were usually 50uA movements giving a

20kOhms/V input impedance e.g. 200k when on the 10V range.

Graham

Reply to
Pooh Bear

I got it 10M using measurement and a little maths! Thanks I couldn't find the manual. I actually threw it out as there isn't that muc hto know about the flke 12 there are only 4 buttons on the thing.

Reply to
Kevin Doyle

"Kevin Doyle" wrote in news:erMBe.2520$ snipped-for-privacy@news.indigo.ie:

You mean like specifications? Smarter to put all your manuals in a file,maybe write the serial number and date of purchase on them at that time. Then if you have anything stolen,you have proof of ownership,and if you choose to sell something,the manual can go along with it.(besides being able to refer back to the manual if needed.)

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Jim Yanik
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Reply to
Jim Yanik

You should really rethink that and get the manual, that fluke is one of the special cases that had V-check and because of that its input impedance can vary a lot, depending on the input voltage. The link to download is

formatting link
If that doesn't work, on the fluke site select: support then manuals, on the drop down list:digitalmultimeters, model 10.

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Steve Sousa
Reply to
Steve Sousa

10/11 Megohm analog meters were built with a dual triode or a pair of FETs to reduce loading the circuit you were working on. AKA VTVM or FET-VOM

They had 10 Megohm input impedance on AC, plus a 1 Megohm resistor in the DC probe to reduce the capacitance of the meter lead to keep it from interfering with the D.U.T.

I can post a schematic to A.B.S.E if you are not familiar with this type of meter.

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Reply to
Michael A. Terrell

Reply to
Kevin Doyle

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