These antique pocket-watch-style electric meters were known as battery testers
...The DC voltmeters and DC ammeters contain copper-wire moving coils, some with jewelled movements, and many are encased in bakelite or metal, which is typically nickel-plated. These portable meters were primarily used to check A, B, and/or C type dry-cell carbon batteries for vacuum tube radio receivers and other electrical apparatus during the time period.
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Pocket Battery Testing Meters
In the days when having a valve "wireless" meant periodically purchasing an expensive High Tension battery and regularly taking your 2 Volt lead acid accumulator to the local radio shop or garage for recharging, it was necessary for the owner to have a means of establishing if the poor performance of the radio was due to "flat" battery or something more serious. These were widely used in the 1920's and 1930's.
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Pocket watch style Voltmeters were first used in the 1880/90s but became widespread during the 1920/30s with most having a brass case that was typically nickel plated though Bakelite examples are known. The case was normally connected to the negative connection, an arrangement that caused numerous electric shocks especially when the rubber insulation within failed. These little testers were used for many tasks but they were designed to be used by Radio Engineer's for measuring the "plate" (anode) voltage of thermionic valves in radios and their grid voltages. The insulated wire that came from the top of the meter was touched onto the negative terminal while the spike/foot was placed on the positive terminal and the reading would be taken from the scale.
Very nice piece, PLC Pie Guy. Even though some of these are around 100 years old, they're not worth a whole lot though. Probably about 25-50 Earth Credits, depending on condition?
Regards,
George
