GU91B
TETRODE
The GU91B tetrode is used for power amplification in travelingwave and singlesideband signal amplifiers, and as a power amplifier in RF equipment.
GENERAL
Cathode: indirectly heated, oxidecoated.
Envelope: metal ceramic.
Cooling: forced air.
Height: a most 95 mm.
Diameter: at most 72 mm.
Mass: at most 600 g.
OPERATING ENVIRONMENTAL CONDITIONS  
Vibration ioads:  
frequencies, Hz  180 
acceleration, m/s², at most  49 
Multiple impacts:  
acceleration, m/s², at most  392 
impact duration, ms, at most  10 
Ambient temperature, °C  60 to +85 
Relative humidity at +35 °C without moisture condensation, %, at most  98 
BASIC DATA Electrical Parameters 

Heater voltage (AC or DC), V  12.6 
Heater current, A  4.14.7 
Anode voltage, V  1,600 
Grid 2 voltage, V  350 
Negative bias voltage, absolute value (at anode current 1,000 mA, anode voltage 1,600 V, grid 2 voltage 350V), V  2055 
Negative cutoff voltage, absolute value (at anode voltage 2,000 V, grid 2 voltage 350 V, anode current 20 mA), V, at most  130 
Grid 2 current (at anode current 1,000 mA, anode voltage 1,600V, grid 2 voltage 350 V), mA  25Þ+10 
Anode current at zero grid 1 voltage, A, at least  2.7 
Mutual conductance (at anode current 1,000 mA, anode voltage 1,600V, grid 2 voltage 350 V), mA/V  3065 
Relative level of combination components of third and fifth orders (at anode voltage 2,000 V, grid 2 voltage 350 V, bias voltage corresponding to quiescent anode current 500 mA, drive voltage equal to bias voltage at frequencies 0.11 MHz), dB, almost  32Þ35 
Output power under conditions of class Â (at anode voltage 1,800 V, ghd 2 voltage 350 V, bias voltage corresponding to quiescent anode current 200 mA, anode current DC component 200 mA at 250±25 MHz), W, at least  700 
Interelectrode capacitance, pF:  
input, at most  86 
output, at most  15 
transfer, at most  0 15 
Limit Operating Values  
Heater voltage (AC or DC), V  12.013.2 
Anode voltage, V:  
DC  2,000 
instantaneous value  3,750 
Grid 2 voltage, V  350 
Negative grid 1 voltage (DC, absolute value), V  150 
Cathodeheater voltage (either polarity, absolute value), V  100 
Cathode current, mA:  
DC component  1,400 
instantaneous value  4,500 
Dissipation, W:  
anode  1,600 
grid 2  20 
grid 1  0.1 
Operating frequency, MHz  250 
Minimum cathode heating time, s  180 
Minimum warm up time, s  300 
Envelope temperature (at hottest point), °C  200 
Averaged Anode Characteristic Curves:
U_{f} = 12.6V; U_{g2} = 350V
Averaged Grid 2Anode Characteristic Curves:
U_{f} = 12.6V; U_{g2} = 350V
Averaged AnodeGrid and Grid Characteristic Curves:
U_{f} = 12.6V; U_{g2} = 350V;
————— I_{g1};
   I_{g2}