This self-contained galvanometer by Rubicon, used to be standard equipment for voltage measurements with a potentiometer. A 6 volt light bulb is used as an optical source, and, after a parallel beam is formed with a stop and a lens, the beam reflects from the mirror on the galvanometer movement, and, after several reflections inside to lengthen the optical lever, falls on the frosted-glass scale. Models with sensitivities as much as 2.5 nano-amperes per millimeter of scale division could be obtained. This instrument sold for about $90 in the 50es. Canrom collection
Canrom Photovoltaics Inc.
3625 Highland Ave
Niagara Falls, New York
USA 14305-0191
phone: +1 (716) 282 2975 Shipping options to be decided