The 8T25RA is a forced air cooled, ceramic—metal medium-mu power triode containing a thoriated tungsten carbide cathode, of which the plate input power up 31kW when operating at Class C. The tube used primally in high frequency heating service.
GENERAL CHARACTERISTICS
Filament Voltage ……………………… 8± 0.5 V
Filament Current ……………………………110 A
Maximum Filament Impact Current ………… 20 A
Amplification Factor……………………………20
Transconductance (Ia=2A) ………………… 24 mA/V
Interelectrode Capacitance
Grid Plate ……………………………… 32 pF
Grid Cathode …………………………… 46 pF
Plate Cathode …………………………… 1.8 pF
Maximum Operation Frequency ……………40 MHz
Maximum Height ………………………… 386 mm
Maximum Diameter ……………………… 204 mm
Apron. Weight …………………………………18 kg
Operation Position ………………Vertical, base down
Cooling ………………………………… Forced Air
Minimum Air Flow ……………………… 25 m3/min
Minimum Static Pressure Intensity ………… 980 Pa
Maximum Operation Temperature …… 250 ℃
Maximum In-coming Air Temperature………… 40 ℃
Maximum Seal and Anode Core Temperature… 250 ℃
MAXIMUM RATING ABSOLUTE ＆#118alue
RF Power Amplifier and Oscillator - Class C Telegraphy
DC Plate Voltage ……………………………14 kV
DC Grid Voltage …………………………… -2 kV
DC Plate Current ………………………… 4.5 A
DC Grid Current ………………………… 0.8 A
Plate Dissipation ………………………… 15 kW
Grid Dissipation ………………………… 400 W TYPICAL OPERATION (Oscillator)
DC Plate Voltage ……………………10 12 kV
DC Plate Current …………………… 4 3.7 A
DC Grid Current ……………………0.4 0.4 A
Grid Impedance……………………2500 2800 Ω
Plate Input Power ……………………28 31 kW
