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Power - Triode ·Triode

4C21

General-purpose directly heated transmitting triode for Class A, B, and C amplifier, modulator, and oscillator service. Rated around 1.25 kV and 100 W plate dissipation, it supports both RF and audio-frequency power applications.

Directly heatedCold cathodeCommon cathodeDissimilar
Sections
1
Base
4AZ
Socket code
J4
Base pins
4
Nominal heater
10 V / 3.25 A

Description

The 4C21 is a general-purpose triode with 10 V, 3.25 A filament and ratings for Class A, Class B, and Class C amplifier, modulator, and oscillator service.

Socket description

Jumbo 4-contact

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base
4AZ
Socket code
J4
Base pins
4
Nominal heater voltage
10 V
Nominal heater current
3.25 A
Parallel heater voltage
-
Parallel heater current
-
Series capable
No

4AZ - 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
Plate resistance
3600 Ω
Transconductance
0.0036 S
Amplification factor
12
Max plate voltage
1250 V
Max plate dissipation
100 W

General maximum plate-voltage/dissipation ratings and salient characteristics promoted; detailed class-service 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

1968 General Electric Co

Published operating points and test conditions from this source.

SECTION 1

Triode

Capacitance

  • Grid-Plate Capacitance

    14.5 pF

  • Input Capacitance

    6 pF

  • Output Capacitance

    5.5 pF

Other

  • Class A Plate Current

    60 mA

    ClassA

  • Class A Plate Power Output

    19.7 W

    ClassA

  • Class B Maximum Signal Power Output

    260 W

    ClassB;TwoTubes