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Power - Triode (over 1000V 100W) ·Triode

F128A

Federal radiation-cooled transmitting triode for modulator, RF amplifier, and oscillator service through about 30 MHz. It provides roughly 700 W plate dissipation and 4 kV capability for medium-power transmitters.

Directly heatedCold cathodeCommon cathodeDissimilar
Sections
1
Base
-
Socket code
-
Base pins
-
Nominal heater
11 V / 13 A

Description

Federal F-128-A radiation-cooled power triode for modulator, RF amplifier and oscillator service, rated through 30 MHz.

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base
-
Socket code
-
Base pins
-
Nominal heater voltage
11 V
Nominal heater current
13 A
Parallel heater voltage
-
Parallel heater current
-
Series capable
No

Terminal pinout

Electrical assignments shared by every tube using this base designation.

No verified pinout is recorded for this base designation.

Section ratings

1 physical section, each with unique specifications.

Section 1

Triode

X-ray radiationInterelectrode capacitances
Amplification factor
36
Max plate voltage
4000 V
Max plate dissipation
700 W
Max grid dissipation
500 W
Max cathode current
600 mA

Highest applicable published maximum ratings promoted; service-specific operating points preserved as parameters.

Source-dependent data

Operating conditions by source

Each block preserves the test conditions and published values from one reference. Values from different sources are intentionally kept separate.

Data set 01

1962 ITT

Published operating points and test conditions from this source.

SECTION 1

Triode

Characteristic

  • Amplification factor

    36

Other

  • Maximum plate voltage

    4000 V

  • Maximum plate dissipation

    600 W

  • Maximum cathode/plate current

    600 mA

  • Maximum frequency for full ratings

    30 MHz

  • Typical RF plate voltage

    3000 V

  • Typical RF output power

    1 kW

Capacitance

  • Grid-plate capacitance

    15.5 pF

  • Grid-filament capacitance

    120 pF

  • Plate-filament capacitance

    45 pF

Construction

  • Cooling method

    Radiation

Data set 02

1962 ITT Industrial and Transmitting Tubes

Published operating points and test conditions from this source.

SECTION 1

Triode

Other

  • AnodeCoolingMethod

    Radiation

  • MaximumOperatingFrequency

    30 MHz

  • Maximum Anode Dissipation

    700 W

    Absolute maximum / applicable service

Capacitance

  • GridPlateCapacitance

    15.5 pF

  • GridFilamentCapacitance

    12 pF

  • PlateFilamentCapacitance

    4.5 pF