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Measuring Standard Cell Voltage

E

Ed Bailen

Jan 1, 1970
0
Can a modern DVM (10 Meg input) be used to measure the voltage of a
standard cell without damaging the cell?

Regards,
Ed Bailen
 
K

Kevin Carney

Jan 1, 1970
0
I would think so.

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"We ought always to know precisely why a given job
is done in a particular way, and why it is done at
all, and why it can't be done more efficiently,
if it must be done at all."-- T.J.Watson

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J

Jim Yanik

Jan 1, 1970
0
Can a modern DVM (10 Meg input) be used to measure the voltage of a
standard cell without damaging the cell?

Regards,
Ed Bailen

No.(well,you will not -damage- the cell,just alter(screw-up) it's
calibrated voltage)

You need a very hi-Z meter(=/> 100Meg) to avoid disturbing the voltage.
SC's were originally measured using the differential voltage method,using a
adjustable voltage source and a null meter.(At null,impedance is extremely
high,theoretically infinite)
 
J

Jim Yanik

Jan 1, 1970
0
No.(well,you will not -damage- the cell,just alter(screw-up) it's
calibrated voltage)

You need a very hi-Z meter(=/> 100Meg) to avoid disturbing the
voltage. SC's were originally measured using the differential voltage
method,using a adjustable voltage source and a null meter.(At
null,impedance is extremely high,theoretically infinite)

To add;you also will not have enough resolution on a DMM to get an accurate
reading of the SC.
 
E

Ed Bailen

Jan 1, 1970
0
To add;you also will not have enough resolution on a DMM to get an accurate
reading of the SC.

Thanks, Jim, I hadn't thought of that.

Ed Bailen
 
W

Watson A.Name - \Watt Sun, the Dark Remover\

Jan 1, 1970
0
Kevin Carney said:
I would think so.

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The small current drawn will greatly affect the accuracy of your
measurement, and probably affect the cell. You should adjust a
precision power supply such as the HP 6111 to the cell voltage, then put
your microvolt meter between the cell and the 6111, and adjust until the
6111 is the same voltage. Then use the 6111 for your measurements. HP
6111 and similar precision PSes go for $40 to $100 on Ebay.
 
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