glutinous wrote:
I have just bought a vintage (1943?) DC 25-kilovolt meter (for a
Steam-Punk style 10kv Jacob's Ladder project).

It is built into a box (photograph attached). On the underside of the
box someone has written:
Meter res = 50 ohm
LV res = 4950
Hi res = 99950

Inside the box are two resistors (one loose, one soldered one end to
an external terminal but not connected to the meter), values:
1 x 4950 ohms
1 x 95k ohm

The meter has three terminals, two main, one smaller in the centre.
The box has two connection terminals and a push-switch, which I
presume was intended to select the appropriate multiplier resistor.

I found an informative piece on rating by Curt Reed at
http://www.antiqueradios.com/forums/...ad4ccd433b5184
(posted: Jul Wed 21, 2010 10:16 pm)

If anyone knows what the central terminal is for, and can offer any
advice on how the meter could be wired for 25kv operation, that would
be better than my guesswork.

Thank you


That meter says "Calibrated at 50 ~", which says to me that it's an AC
microammeter with a display in volts.

Use with care.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal
ElectroOptical Innovations
55 Orchard Rd
Briarcliff Manor NY 10510
845-480-2058
hobbs at electrooptical dot net
http://electrooptical.net