why does voltmeter show voltage ?

Thread Starter

ol'trusty

Joined Sep 9, 2009
48
I am looking for an explanation on why does a voltmeter show voltage when on dc volt mode and I connect a capacitor ? Also when I touch both ends it shows between 100-300 millivolts (or put it on my tongue for example).

Can someone please explain this..

Thanks
Trusty
 

bountyhunter

Joined Sep 7, 2009
2,512
Most modrn meters have an input impedance of 10 MEG ohms which means even a very small amount of noise picked up on the test leads will generate a voltage which it will display.
 

hobbyist

Joined Aug 10, 2008
887
Because of the high input resistance as mentioned above,your getting phantom readings so no matter what you touch on your body with the probes a phantom reading will show a steady display the moment the probes are touched.
 

ELECTRONERD

Joined May 26, 2009
1,147
A good experiment to prove this noise is to get an oscilloscope and touch the center conductor of the probe (don't touch ground!). You will get a oscillation on the scope which will be quite distorted, likely in the mV range.

Austin
 
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