GU68A
TRIODE
The GU68A triode is used for power amplification at up to 30 MHz in stationary RF transmitters.
GENERAL
Cathode: directly heated, carbonized thoriated tungsten.
Envelope: metalceramic.
Cooling: forced (water for anode, air for stem).
Height: at most 530 mm.
Diameter: at most 215 mm.
Mass: at most 24 kg.
OPERATING ENVIRONMENTAL CONDITIONS  
Ambient temperature, °C  10 to +55 
Relative humidity at up to +25 °C, %  98 
BASIC DATA Electrical Parameters 

Filament voltage, V  20 
Filament current, A  300330 
Mutual conductance (at anode voltage 1 kV, anode currents 10 and 14 A), mA/V  115145 
Gain coefficient (at anode voltage 1 and 2 kV, anode current 10 A)  3038 
Anode current (at anode voltage 0.3 kV, grid voltage 100 V), A, at least  8 
Negative cutoff voltage (at anode voltage 10 kV, anode current 0.1 A), absolute value, V, at most  400 
Interelectrode capacitance, pF:  
input, at most  300 
output, at most  6 
transfer, at most  105 
Limit Operating Values  
Filament voltage (AC or DC), V  1921 
Anode voltage (DC), kV  12 
Cutoff voltage, absolute value, kV  1.5 
Filament starting current, A  450 
Dissipation, kW:  
anode  130 
grid  2.3 
Operating frequency, MHz  30 
Temperature at stem and metaltoceramic seals, °C  175 
Averaged Anode Characteristic Curves
Averaged Characteristic Curves:
_____ anodegrid;
_ _ _ grid
Averaged GridAnode Characteristic Curves