IM-17 Batteries

[Garey Barrell]

John -

There really isn't a good replacement for a mercury cell.  There are
many ways to get 8.4 V from a 9V battery, but the absolute voltage isn't
the problem.  All batteries EXCEPT for the mercury battery have a
"slope" discharge curve.  i.e., the voltage starts to decrease almost
immediately, and continues until it reaches the minimum that will
operate the equipment.

On the other hand, a mercury battery has an almost flat discharge
"curve" until just before end of life when it drops like a rock.  This
is important for things like watches, light meters for photography,
voltmeters or anything else that relies on a stable voltage.

Photographers have gone to great lengths to make accommodations to keep
their light meters accurate.  The only "good" answer is a voltage
regulator, but not many regulators will regulate with less than a volt
to work with.

73, Garey, K4OAH
Atlanta



John Barkow wrote:
> Anyone know of a replacement for the 8.4V mercury battery for this unit other
> than a 9V battery?
> Thanks, John kd6pt
>
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