FET voltmeter sought

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Suppose a fellow wished to buy a high input impedence voltmeter rather  
accurate for low voltages (< 10v, say) but not expensive.  Any  
recommendations?

Re: FET voltmeter sought
Peter Percival schrieb:
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What do you mean with "high"? Digital multimeters normally have an
input impedance of 10 MOhms; the lowest measuring range is 0.2 volts.

Best regards

Reinhard

Re: FET voltmeter sought
Reinhard Zwirner wrote:
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50 Mohms down to 0.01 volts.  Is that too much to ask?
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Re: FET voltmeter sought
On 03/14/2016 08:40 AM, Peter Percival wrote:
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A 50 M precision series resistor (probably a series combination),  
measuring on the microamp range.  You have 1 pA resolution there, which  
is 100 uV.  You do have to watch the burden voltage, of course.

Cheers

Phil


Re: FET voltmeter sought
Phil Hobbs wrote:
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Thank you.


Re: FET voltmeter sought
On 3/14/2016 7:40 AM, Peter Percival wrote:
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  You could put a 40M resistor in series and divide the reading by 5.
0.002V x 5 = 0.01V So, I guess you would need a 4-1/2 digit multi meter.
Or is that 3-1/2?

                                   Mikek

Re: FET voltmeter sought
On Sat, 12 Mar 2016 15:53:37 +0000 Peter Percival

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If you want fairly cheap:
HP 3478A has an input impedance of >100Gohm on it's 3VDC or less ranges.
HP 3456A has an input impedance of >100Gohm on it's 10VDC or less ranges,
but size is a bit large.

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