GU94A
TETRODE
The GU94A tetrode is designed for use in stationary pulsemodulation RF equipment at frequencies up to 2 MHz for output power 150 kW and at up to 30 MHz for output power 100 kW.
GENERAL
Cathode: directly heated, carbonized thoriated tungsten.
Envelope: metalceramic.
Cooling: forced (water for anode, air for other envelope elements)
Working position: upright with anode up or down.
Height: at most 535 mm.
Diameter: at most 221 mm.
Mass at most 35 kg.
OPERATING ENVIRONMENTAL CONDITIONS  
Vibration loads:  
frequencies, Hz  135 
acceleration, m/s²  5 
Multiple impacts with acceleration, m/s²  150 
Ambient temperature, °C  155 
Relative humidity at up to 25 °C, %  98 
BASIC DATA Electrical Parameters 

Filament voltage (AC or DC), V  18 
Filament current, A  340420 
Peak anode current (at filament voltage 18 V, anode voltage 2.5 kV, grid 2 voltage 1.5 kV, grid 1 voltage 0), A, at least  38 
Negative cutoff voltage, absolute value (at filament voltage 18 V, anode voltage 2 kV, grid 2 voltage 1.5 kV, grid 1 voltage 0), V, at most  350 
Mutual conductance (at filament voltage 18 V, anode voltage 2 kV, grid 2 voltage 1.5 kV, anode current 6 and 10A),mA/V  110180 
Cathode emission current (at filament voltage 18 V, anode voltage 1 kV, grid 2 voltage 1 kV), A, at least  190 
Output power (at anode voltage 12 kV), kW:  
at 2 MHz, at least  150 
at 26 MHz, at least  100 
Interelectrode capacitance in agroundedcathode circuit, pF:  
input  550650 
output  6077 
transfer, a most  2.6 
Limit Operating Values  
Filament voltage, V  18.5 
Anode voltage (DC), kV:  
in modulation mode  15 
in anodescreen modulation mode  12.5 
Grid 2 voltage (DC), kV:  
in modulation mode  1.8 
in anodescreen modulation mode  0.9 
Negative bias voltage, absolute value, kV  0.6 
Filament starting current (peak value), A  800 
Dissipation, kW:  
anode  160 
grid 2  2.5 
grid 1  0.5 
Operating frequency, MHz  30 
Envelope temperature, °C  175 
Emission Characteristic Curves
AnodeGrid Characteristic Curves:
U_{f} = 18V; U_{g2} = 1,000V
AnodeGrid Characteristic Curves:
U_{f} = 18V; U_{g2} = 1,500V
Grid Characteristic Curves:
U_{f}=18V; U_{a} = 1.8kV
Grid Characteristic Curves:
U_{f} = 18V; U_{g2} = 1,000V
Grid Characteristic Curves:
U_{f} = 18V; U_{g2} = 1,500V