On Fri, 03 Sep 2010 08:34:34 -0400, PeterD wrote:

On Thu, 02 Sep 2010 21:31:25 +0100, glutinous
wrote:

On the image the meter says "FS 254V" or something like that. Exactly
what is the number, where is the decimal point (if there is on)? This
will be the full scale voltage reading, most likely. I'd connect the
bare meter to a variable AC source (start at a very low voltage,
perhaps a volt or so) and see what reading, and current is drawn by
this meter.

Also, clearly the meter was salvaged from something else, so I suspect
that what you have is something that was kobbled together by a hobiest
like Jon, designed to kill the unwary. I'd be very, very careful about
applying more than a few hundred volts to it.

Thank you very much for the reply, Peter.

There is no decimal point, it's:
F.S. 254V.

Since this is near as dammit to the UK mains voltage, I'd rather
thought that was its reference point. I'd also assumed that the meter
was AC (hence the 'calibrated at 50~') but supposed that in use it was
intended to be fed via rectification: though on opening the box there
is none.

The Jacob's Ladder I referred to is built and functions well, using
(and I always get a childish pleasure out of saying this) a 10kv FART
transformer from a neon rig.

I was thinking of doing something along the lines you more precisely
suggest, as against just whacking the full 10kv through the larger
resistor just to see what happened... Standing well back and with a
camcorder running, o.c. ...