In article , DoN. Nichols says...

Can you find anything which might be a date code on them? the
"7 MF" designation sounds really old.

Some manufacturers never really caught on to the appropriate
nomenclature.

I wonder about the internal resistor. It could either be a
parallel resistor to safely discharge it when the power source goes
away, or a series resistor to limit the current available from discharge.

The resistor is most likely to prevent self-charging. My old boss
used to store these with a wire shunt across the terminals - he
claimed that cosmic rays would charge them up over time.

As for the best use? As already mentioned, you just wave them
around (working end pointing outward of course) at your buddies.
Doesn't matter if you charged them up or not, you get a great
reaction either way!

Jim


--
==================================================
please reply to:
JRR(zero) at pkmfgvm4 (dot) vnet (dot) ibm (dot) com
==================================================