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 500 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
