[Milsurplus] RF Ammeter Question

[J. Forster]

You can easily tell if the thing has an internal shunt by running some DC
current through it and a series limiting resistor, first one way, then the
other.

If the meter indicates positive, irrespective of the current direction, it
has a TC.

If the meter reads upscale one way, and downscale the other, it has no TC.

You can also apply 60 Hz AC through a resistor. If it indicated upscale,
it has a TC.

The meter should have response from 50 Hz to 10s of MHz roughly.

It is odd to see a current meter with a resistor paralleling the terminals.

-John

============




> I rescued what looks to be a perfectly good Simpson RF Ammeter from the
> clubs trash can a while back.  It’s a 3 inch square panel meter, 0 to
> 2.5A,
> logarithmic scale,  with a 0.05 ohm 25W resistor solder to the terminals.
>
>
>
> I’m not sure how to tell if this has an internal thermocouple.  I did some
> web searching and it seems Simpson did make these types with the internal
> thermocouple, but I haven’t found anything that tells how I can verify.
>
>
>
> I’ve never used an RF Ammeter before, so I assume I use it just as a good
> old DC Ammeter?   Is there a frequency limitation?
>
>
>
> Thanks
>
>
>
> Mark K3MSB
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