Could be anything. I flew them for about 2500 hours, and the horizons
were vacuum powered. Any other electric ones could be whatever they
got approved and installed. Our DG's were vacuum also. Airspeed
indicators were direct reading gauges. The ones I flew were about half
ex-American airlines with the doors on the right side, and the others
were at one time Trans Texas Airways, later becoming Texas
International. Seems I remember the cockpit lighting was 24 volts.
The 3's pretty much pre-dated electric instruments.
Rich

On Mon, 6 Sep 2010 13:07:25 -0600, "Pintlar"
wrote:

Anyone know the voltage that is used for the instruments on a C-47 control
panel?
Specifically for the Artificial Horizon.
in advance, thanks. . .charlie