[Test-Equipment] Standard Cell Voltage variation

[John Barnes]

Hi,

I have been following the thread on old test equipment, which changed to a
discussion on standard cells.

Here is my question:

I have a Guildline 9152/4 Standard Cell enclosure that is fitted with 4
saturated standard cells. The cells are held at a temperature of 30 +/- 0.01
C.

At one time this type of cell was used as a transfer standard, before being
replaced by solid state units like the Fluke 732.

When I measure the cells I find that two of pairs of the cells agree with
each other by 1 uV. But the pairs disagree with each other by 25 uV.

I do not have the history on this unit. Is this a normal variation for this
type of standard cell ?

The voltages are:

Cell 1  1.018129
Cell 2  1.018130
Cell 3  1.018154
Cell 4  1.018155

Measured with a Fluke 8506 or HP 3456

Can anybody help ??

Regards,


John Barnes