F9C28

Power transmitting triode intended for RF amplification, oscillation, or modulation. Manufacturer documentation emphasizes professional transmitter or industrial RF service with substantial plate voltage, current, and output capability.

Directly heatedCold cathodeCommon cathodeDissimilar

Sections: 1
Base: -
Socket code: -
Base pins: -
Nominal heater: 15 V / 135 A

Description

Federal F-9C28 low-mu three-electrode modulator tube for Class AB1 audio-frequency service. It uses a thoriated-tungsten multistrand filament and a water-cooled anode capable of 40 kW dissipation.

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: 15 V
Nominal heater current: 135 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: 4.75
Max plate voltage: 15000 V
Max plate dissipation: 40000 W
Max cathode current: 45 A

Published ratings/characteristics semantically audited; condition-specific operating values preserved in parameter rows.

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
4.75

Other

Maximum plate voltage
15000 V
Maximum plate dissipation
40000 W
Peak cathode current
45 A
Maximum/full-ratings frequency
0.02 MHz
Typical Class-AB output power
39 kW

Capacitance

Grid-plate capacitance
45 pF
Grid-filament capacitance
56 pF
Plate-filament capacitance
20 pF

Construction

Cooling method
Water

Data set 02

1962 ITT Industrial and Transmitting Tubes

Published operating points and test conditions from this source.

SECTION 1

Triode

Characteristics

Amplification factor
4.75
Peak cathode current
45 A

Other

Filament starting current
200 A
Maximum
DC plate voltage
15000 V
ClassAB1 Audio
Maximum signal DC plate current
10 A
ClassAB1 Audio
Maximum signal plate input
100 kW
ClassAB1 Audio
Plate dissipation
40 kW
ClassAB1 Audio
Typical DC plate voltage
10000 V
ClassAB1 Audio
Typical DC plate voltage
12000 V
ClassAB1 Audio
Maximum signal power output
39 kW
ClassAB1 Audio

Capacitance

Grid-plate capacitance
45 pF
Grid-filament capacitance
56 pF
Plate-filament capacitance
20 pF