Description
811A is direct-heated type thorium tungsten cathode high µ triode, can be used as high-frequency oscillation power amplification.
811 is similar to 811A, they can be exchanged each other.
Heater
Uf————————————–6.3 V
If—————————————4 A
Maximum Rating
Ua————————————–1250 V
Ia—————————————125 mA
Pa————————————–40W
grid current—————————————50 mA
Operating frequency and Ua
When the operating frequency above 30MC, Ua and anode input power should be reduced as follows:
Operating frequency(MC) Ua and anode input power
60 89%
80 70%
100 55%
When it is in constant working, the anode should not be allowed to have slight red; when in interrupted working, it should only be allowed to have perceptible slight red.
Direct Interelectrode Capacitances
Input————————————–5.5 PF
output————————————–0.6 PF
Grid to plate……………………………………………..5.5 PF
Static parameter:
Ua……………………………………………………….2000 V
-Ug………………………………………………………2 V
Ia………………………………………………………26 mA
µ(Ia=20mA)……………………………………..160
Maximum rating in other operating conditions
R-F power amplifier or oscillation, C amplifier (CW)
CCS ICAS
Ua………………………………….1250 1500 V
Ia……………………………………175 175 Ma
Pa…………………………………..45 65 W
Pa (in)……………………………..175 260 W
Ug…………………………………-200 -200 V
Ig…………………………………..55 50 mA
C amplifier anode-modulation, R-F power amplifier
CCS ICAS
Ua…………………………………1000 1250 V
Ia…………………………………..125 150 mA
Pa………………………………….30 45 W
Pa (in)……………………………115 175 W
Ug…………………………………-200 -200 V
Ig……………………………………50 50 mA
CCS: constant working
ICAS: interrupted working
A-F power amplifier or oscillation
B amplifier, grid driving
Maximum Rating
CCS ICAS
Ua………………………………………………1250 1500 V
Ia (max. sig)……………………………….175 175 mA
Pa………………………………………………45 65 W
Pa (in) (max. sig)……………………165 235 W
Recommended operating condition (Reference value)
(The value of two tubes)
CCS ICAS
Ua……………………………………………1250 1500 V
Ug…………………………………………….0 -4.5 V
Ia (0)…………………………………………50 32 mA
Ia (max .sig)……………………………..260 313 Ma
Ũg (pk)……………………………………145 170 V
Pd (max. sig)…………………………..3.8 4.4 W
RL (a-a)……………………………………12.4 12.4 kΩ
Pout (max. sig)…………………………235 340 W
