Summary

CAT 9 triode, transmitting, 2 examples. Made by Marconi Wireless Telegraph Company Limited circa 1941. In original wooden packing case.
These tubes were used at Maribynong Optical Works during World War 2 in a radio frequency furnace. The furnace was used for melting precious metals such as platinum.
These types of valve are handmade and so each has slightly different electrical and physical characteristics.
Peak plate voltage usable with these tubes is 15 kilovolt; the filament is 18 volts at 100 amps.

Physical Description

Two valves, each is a cylindrical glass bulb connected to cylindrical copper anode. 2 pins on end of glass tube and metal threaded boss on other end, Valve also fitted with a pair of corona rings; bottom ring provides air cooling for bulb. Grid connection projects on one side and exhaust tip on the opposite side. In one valve, one corona ring is loose. Original packing case is not in same location.

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