The EMI Emitron Tube

Typical operating voltages:-
Second anode & mosaic 0v.
First anode - 800v.
Cathode - 1500v.

Control Grid - 1550v.

EMI patent by Tedham, William F., and McGee, James D., filed May 1932, and patented 1934. "Improvements in or relating to cathode ray tubes and the like". Patent No. GB 406,353.