Tube-number record
F-212-E
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BrandFederal Telephone and Radio Corporation
ClassPower Triode
Construction
Primary TypeTriode
EnvelopeGlass
Sections1
Filament / Heater
MaterialThoriated tungsten
Absolute Maximum Ratings
Plate Voltage2000 V
Plate Dissipation275 W
Grid 1 Voltage-500 V
Cathode Current350 mA
Audio Performance
Typical THD4%
Power Output75 W
Key Features
- Radiation-cooled anode
- Thoriated tungsten filament
- Four impedance classes for parallel operation
- High power output up to 840 Watts in Class B AF pairs
Typical Operation
| Mode | Plate V | Gm (µmhos) | Rp (Ω) | µ | Plate mA |
|---|---|---|---|---|---|
| Audio-Frequency Power Amplifier and Modulator - Class A | 2000 V | — | — | 16 | 130 mA |
| Audio-Frequency Power Amplifier and Modulator - Class B (per tube values) | 2000 V | — | — | 16 | 300 mA |
| Radio-Frequency Power Amplifier - Class B | 1600 V | — | — |
Application Notes
Tubes are categorized into four impedance classes (1, 2, 3, 4) to facilitate parallel operation using a common grid bias. When using multiple tubes, same or adjacent classes should be employed for even load distribution.
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