Valve tester for 2 volt battery valves


With the age and delicate filaments of 70 year old battery valves it seemed a good idea to have some means of checking not only filament continuity but also filament emission. and working characteristics. (Also it was something "to do!")

Small and simple was the objective. The answer came in the form of a device drawing it`s power from existing equipment - a stabilised variable DC power supply and an AC variac. With these power supplies the tester is not totally isolated from the AC mains, so some caution is necessary and the equipment is housed in a wooden insulating case It could be modified to operate from an existing mains isolated power supply,but then loses some of it`s simplicity.

The photograph shows a Cossor 220 P on test.

The item beside the unit is a piece of high tech equipment, a valve base with a torch bulb soldered in, much safer than an elderly valve for a first switch on.


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