5642
The 5642 is a directly-heated high-voltage rectifier tube.
- filament volatage = 1.25V
- filament current = 200mA
- peak inverse volrage = 10kV
- peak plate current = 250uA
It is used in the CRT cathode and post-deflection acceleration supplies in many Tektronix scopes. In typical CRT circuits, the filament/cathode leads of each 5642 have their own secondary winding on the HV transformer.