GU71B
PENTODE
The GU71B pentode is used for singlesideband power amplification and for power amplification at frequencies up to 75 MHz in stationary generalpurpose RF equipment.
GENERAL
Cathode: indirectly heated, oxidecoated.
Envelope: metaltoceramic, with ring leads or grids and cathodeheater and pin leads of heater.
Cooling: forced air.
Height: at most 165 mm.
Diameter: at most 101 mm.
Mass: at most 1.7 kg.
OPERATING ENVIRONMENTAL CONDITIONS  
Vibration loads:  
frequencies, Hz  50 
acceleration, m/s²  25 
Multiple impacts with acceleration, m/s²  118 
Lowest permissible ambient temperature, °C  60 
Relative humidity at up to +35 °C, %  9598 
BASIC DATA Electrical Parameters 

Heater voltage (AC or DC), V  12.6 
Heater current, A  6.87.5 
Anode voltage (DC), kV  35 
Grid 3 voltage, V  0 
Grid 2 voltage (DC), V  517 
Negative grid 1 voltage, absolute value, V, at most  80 
Anode current (at heater voltage 11.3 V), A, at least  1.2 
Grid 2 current, A, at most  92 
Mutual conductance, mA/V  5272 
Voltage level of combination frequencies of third and fifth orders relative to main current voltage (at anode voltage 3 kV, anode current 850 mA, grid 2 current at most 92 mA and frequency of oscillations 70 MHz), dB, at most  39 
Cathode heating time, s, at most  210 
Oscillatory power under class AB_{1} amplification (at anode voltage 3 kV, grid 2 current at most 92 mA and frequency of oscillations 0.1 MHz), kW, at least  1.3 
Interelectrode capacitance, pF:  
input  115150 
output, at most  35 
transfer,at most  0.15 
Limit Operating Values  
Heater voltage (AC or DC), V  1213.2 
Anode voltage, kV  3.5 
Peak anode voltage, kV  6.5 
Grid 2 voltage, V  400 
Grid 1 voltage, absolute value, V  100 
Grid 3 voltage, V  0 
Dissipation, W:  
anode  1.5x10³ 
grid 2  32 
grid 1  3 
Operating frequency, MHz  75 
Cathode heating time, s  210 
Temperature at stem, anode and metaltoceramic seals, °C  200 
Averaged Characteristic Curves:
U_{f} = 12.6V; U_{g2} = 350V; U_{g3} = 0;
_____ anode;
_ _ _ grid 2anode;
 • — P_{a max}
Averaged Characteristic Curves:
U_{f} = 12.6V; U_{g2} = 400V; U_{g3} = 0;
_____ anode;
_ _ _ grid 2anode;
 • — P_{a max}
Averaged AnodeGrid Characteristic Curves:
U_{f} = 12.6V; U_{g2} = 350V; U_{g3} = 0
Averaged AnodeGrid Characteristic Curves:
U_{f} = 12.6V; U_{g2} = 400V; U_{g3} = 0