Got a Dumb Question

[old_coot88]

Never having owned a digital multimeter, what is the input impedance (when measuring voltage) of a typical DMM? I'd assume it's FET based and comparable to a VTVM , but can't find any info specific to input impedance.

[Electronic M]

It varies by model. Some of the China loss leader stuff isn't much better than a VOM, and some of the mid to high end stuff is better than a good VTVM.
It'll always be in the specifications page of the manual (unless your DMM really scrapes the bottom of the barrel) and the manual will almost always be free online with a simple Google search.

Find some model numbers of stuff that interests you and Google brand model number manual of it and the specs should be there.

[MIPS]

Impedance for a half-decent Chinesium multimeter should be 2 megaohms or greater.

[Tim]

Name brands such as Fluke and Tektronix are typically 10meg

[jr_tech]

Originally Posted by MIPS

Impedance for a half-decent Chinesium multimeter should be 2 megaohms or greater.

7 to 11 megohms for the ones that I have (must’ve got lucky ). My Tektronix meters are indeed 10 megohms.

jr

[bandersen]

Yep. Both my old Fulke 27/FM and cheap modern meter are 10 megs.

[old_coot88]

Thanks fellers.

[vortalexfan]

10 Megs is what I was thinking too, because isn't that the standard input impedance on your Oscilloscopes and some of your signal generators?

[bandersen]

Scopes are typically 1Meg but they are usually paired with a X10 probe that gets it up to 10 Meg.