4CX125C

High-power ceramic/metal transmitting tetrode designed for RF power amplification, linear amplification, oscillation, modulation, broadcast, or related high-power service.

Directly heatedCold cathodeCommon cathodeDissimilar

Sections: 1
Base: -
Socket code: -
Base pins: -
Nominal heater: 6 V / 2.6 A

Description

Horizontally-finned radial-beam power tetrode based on the 4CX300A, intended for RF amplifier service with transverse forced-air cooling.

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: 6 V
Nominal heater current: 2.6 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

Tetrode

X-ray radiationInterelectrode capacitances

Transconductance: 0.012 S
Max plate voltage: 2000 V
Max screen voltage: 400 V
Max plate dissipation: 125 W
Max screen dissipation: 12 W
Max grid dissipation: 2 W

Published absolute maximum ratings promoted from the applicable service tables; pulse-service maxima are used only where explicitly noted in the tube note.

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 Eimac

Published operating points and test conditions from this source.

SECTION 1

Tetrode

Other

Heater/Filament Voltage
6 V
Frequency for Maximum Ratings
500 MHz
Maximum Plate Voltage
2000 V
Highest published applicable absolute maximum
Maximum Screen Voltage
400 V
Highest published applicable absolute maximum
Maximum Plate Dissipation
125 W
Maximum Screen Dissipation
12 W
Maximum Grid Dissipation
2 W
Maximum DC Plate Current
250 mA
Heater Current
2.6 A to 3.1 A
4CX125C
Cathode-to-Heater Potential
-150 to 150 V
Plate Voltage
2000 V
ClassC;RFAmplifier
Plate Output Power
390 W
ClassC;TelegraphyOrFMTelephony

Characteristic

Transconductance
12000 uS
Heating Time
30 to 60 s
Grid-Screen Amplification Factor
4 to 5.6
Published range

Capacitance

Output Capacitance
3.5 to 4.5 pF
GroundedCathode
Feedback Capacitance
- to 0.06 pF
GroundedCathode