VOLTMETERS

Many instrument companies manufactured analog devices for measuring voltage. These instruments are basically calibrated galvanomers with precision resistances in series of the moving coil. Here I show an early voltmeter produced by Evershed and Vignoles, the inventors of the famous megger resistance meter. Typical for all their instruments is the metal lid that covers the glass window of the meter.

The tiny voltmeter GPO Nr4 was the standard outfit for a telephone engineer. It is a very robust device that is carried around in a leather case with a strap. The instrument on its own is a voltmeter, but a set of shunts is available for measuring currents as well.