MH4 MOV CATKIN VALVE, 1932

The Marconi Osram Valve Company developed the MH4. An indirectly heated Triode, that became the general purpose valve for set makers in the 30's. And was the worlds first all metal valve, the case of this valve (Anode) carried the full HT voltage. See Item A0638 for a Catkin with a cover.

A0637