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ACT25 / CV436 transmitting triode, 13.5V/2.8A heater.

The serial number 31 is written on the valve.

See below for internal details of this valve.


Heater voltage 15V
Heater current 3A
Max DC anode voltage 1kV
Max pulse anode voltage 6kV
Max anode dissipation 450W
Max peak space current (cw) 6A
Min peak emission 60A
Amplification factor * 80
Mutual conductance * 30mA/V
Efficiency at 500MHz with 7db gain 60%
Efficiency at 1GHz with 3db gain 30%
Cag 13.0pF
Cgc 22.0pF
Cac 0.4pF

*: At Va=1kV, Ia=250mA

Connections: As shown in the main picture, the anode is at the bottom, the grid is the large ring, heater/cathode the smaller ring above and heater the top connection.


Top and bottom views ACT25 top view ACT25 base view
Inside view of the anode block Anode
Cathode and heater details Cathode heater connection
Closeups of the grid Grid Grid Grid



Disassembled ACT25 donated by Michael Porter

This file was last modified 14:54:43, Tuesday September 02, 2014