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Voltage - Dual Triode (similar) ·Triode-Triode

2C21

Medium-mu twin triode, co-designated with 1642, intended for Class-A amplifier service and providing two similar triode units in a compact receiving-type envelope.

Directly heatedCold cathodeCommon cathodeDissimilar
Sections
2
Base
7BH
Socket code
-
Base pins
7
Nominal heater
6.3 V / 600 mA

Description

Medium-mu twin triode, co-designated 2C21/1642, for Class-A amplifier service.

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base
7BH
Socket code
-
Base pins
7
Nominal heater voltage
6.3 V
Nominal heater current
600 mA
Parallel heater voltage
-
Parallel heater current
-
Series capable
No

7BH - Terminal pinout

Electrical assignments shared by every tube using this base designation.

No verified pinout is recorded for this base designation.

Section ratings

2 physical sections, each with unique specifications.

Section 1

Triode

X-ray radiationInterelectrode capacitances
Plate resistance
7600 Ω
Transconductance
0.001375 S
Amplification factor
10.4
Max plate voltage
250 V

Promoted from the printed maximum-rating/characteristic columns; additional operating-point and capacitance data are retained in TUBE_SECTION_PARAMETER.

Section 2

Triode

X-ray radiationInterelectrode capacitances
Plate resistance
7600 Ω
Transconductance
0.001375 S
Amplification factor
10.4
Max plate voltage
250 V

Second physical triode section; electrically identical twin section.

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

195X General Electric Essential Characteristics

Published operating points and test conditions from this source.

SECTION 1

Triode

Other

  • Plate voltage

    250 V

    ClassA;EachSection

  • Control-grid voltage

    -16.5 V

    ClassA;EachSection

  • Plate current

    8.3 mA

    ClassA;EachSection

Characteristic

  • Plate resistance

    7600 Ω

    EachSection

  • Transconductance

    1375 µS

    EachSection

  • Amplification factor

    10.4

    EachSection