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GU-21B

TRIODE

The GU-21 B triode is designed for use as an amplifier or oscillator tube at frequencies up to 26 MHz in grounded-grid circuits and in circuits with neutralization.

GENERAL
Cathode: directly heated, carbonized thonated tungsten.
Envelope: glass-to-metal with grid ring.
Cooling: forced air.
Height: at most 355 mm.
Diameter: at most 142 mm.
Mass: at most 8 kg.

gu-21b(2)1.jpg

OPERATING ENVIRONMENTAL CONDITIONS
Ambient temperature, °C	10 to -55
Relative humidity at up to +25°25, %	98

BASIC DATA
Electrical Parameters

Filament voltage, V 8.3

Filament current, A 140-160

Mutual conductance (at anode voltage 2 kV, anode currents 2 and 4 A), mA/V 25-35

Gain coefficient (at anode voltages 2 and 5 kV and anode current 2 A) 41-55

Anode current at zero grid voltage (at anode voltage 5 kV), A 1.1-2.3

Interelectrode capacitance, pF:

input, at most 55

output, at most 1.5

transfer, at most 45

Limit Operating Values

Filament voltage, V 7.8-8.3

Anode voltage, kV 9

Filament starting current, A 225

Dissipation, W:

anode 1.0x10₄

grid 600

Operating frequency, MHz 26

Temperature at envelope, stem and seals, °C 150

BASIC DATA Electrical Parameters
Filament voltage, V	8.3
Filament current, A	140-160
Mutual conductance (at anode voltage 2 kV, anode currents 2 and 4 A), mA/V	25-35
Gain coefficient (at anode voltages 2 and 5 kV and anode current 2 A)	41-55
Anode current at zero grid voltage (at anode voltage 5 kV), A	1.1-2.3
Interelectrode capacitance, pF:
input, at most	55
output, at most	1.5
transfer, at most	45

Limit Operating Values
Filament voltage, V	7.8-8.3
Anode voltage, kV	9
Filament starting current, A	225
Dissipation, W:
anode	1.0x10₄
grid	600
Operating frequency, MHz	26
Temperature at envelope, stem and seals, °C	150