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Voltage - Triode (with diode, heptode or hexode) ·Heptode-Triode

2G21

Ultra-low-power triode-heptode for battery receiver oscillator and frequency-converter service. The triode provides local oscillation while the heptode performs mixing from very modest filament and plate supplies.

Directly heatedCold cathodeCommon cathodeDissimilar
Sections
2
Base
2G21
Socket code
B7G
Base pins
7
Nominal heater
1.25 V / 50 mA

Description

Directly heated subminiature triode-heptode frequency converter for low-voltage battery radio equipment.

Socket description

Miniature 7-contact

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base
2G21
Socket code
B7G
Base pins
7
Nominal heater voltage
1.25 V
Nominal heater current
50 mA
Parallel heater voltage
-
Parallel heater current
-
Series capable
No

2G21 - 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
Transconductance
0.0006 S
Amplification factor
20
Max plate voltage
50 V
Max plate dissipation
0.1 W
Max cathode current
2 mA

Promoted from clearly identified printed ratings/characteristics; additional published operating points and capacitances retained in TUBE_SECTION_PARAMETER.

Section 2

Heptode

X-ray radiationInterelectrode capacitances
Plate resistance
500000 Ω
Transconductance
0.00006 S
Max plate voltage
45 V
Max screen voltage
45 V
Max plate dissipation
0.1 W
Max cathode current
2.2 mA

Promoted from clearly identified printed ratings/characteristics; additional published operating points and capacitances retained in TUBE_SECTION_PARAMETER.

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

1938 Raytheon

Published operating points and test conditions from this source.

SECTION 1

Triode

Other

  • HeaterVoltageNominal

    1.25 V

    Nominal

  • HeaterCurrentNominal

    50 mA

    Nominal

  • Maximum Plate Voltage

    45 V

  • Maximum Plate Dissipation

    0.1 W

  • Maximum Cathode Current

    2 mA

Characteristic

  • Transconductance

    600 µS

    Typical

  • Amplification Factor

    20

    Typical

SECTION 2

Heptode

Other

  • HeaterVoltageNominal

    1.25 V

    Nominal

  • HeaterCurrentNominal

    50 mA

    Nominal

  • Maximum Plate Voltage

    45 V

  • Maximum Screen Voltage

    45 V

  • Maximum Plate Dissipation

    0.1 W

  • Maximum Cathode Current

    2 mA

Characteristic

  • Transconductance

    250 µS

    Typical

Data set 02

195X General Electric Essential Characteristics

Published operating points and test conditions from this source.

SECTION 1

Triode

Other

  • Oscillator plate voltage

    22.5 V

    Converter

  • Oscillator plate current

    1 mA

    Converter

  • Oscillator grid current

    0.03 mA

    Converter

  • Oscillator grid resistor

    50000 Ω

    Converter

SECTION 2

Heptode

Other

  • Plate voltage

    22.5 V

    Converter

  • Screen voltage

    22.5 V

    Converter

  • Control-grid voltage

    0 V

    Converter

  • Plate current

    0.2 mA

    Converter

  • Screen current

    0.3 mA

    Converter

Characteristic

  • Plate resistance

    500000 Ω

    Converter

  • Conversion transconductance

    60 µS

    Converter

Data set 03

195X Raytheon Special Purpose Tubes

Published operating points and test conditions from this source.

SECTION 1

Triode

Other

  • Plate Voltage

    22.5 V

    TriodeSection

  • Plate Current

    1 mA

    TriodeSection

SECTION 2

Heptode

Other

  • Plate Voltage

    22.5 V

  • Grid 1 Voltage

    Rg=50000 ohm V

  • Grid 2 Voltage

    22.5 V

  • Grid 3 Voltage

    0 V

  • Plate Current

    0.2 mA

  • Grid 2 Current

    0.3 mA

Characteristic

  • Transconductance

    60 uS

  • Plate Resistance

    0.5 Mohm

Data set 04

1960 Mazda

Published operating points and test conditions from this source.

SECTION 1

Triode

Other

  • Triode anode voltage

    45 V

  • Heptode anode voltage

    45 V

Capacitance

  • Grid 3 to heptode anode capacitance

    0.065 pF

  • Grid 1 to triode anode capacitance

    1.3 pF

Data set 05

1968 Mazda Belvu

Published operating points and test conditions from this source.

SECTION 1

Triode

Characteristics

  • Heater or filament voltage

    1.25 V

    Published nominal value

  • Heater or filament current

    53 mA

    Published nominal value

  • Conversion transconductance

    75 µA/V

    Published nominal

SECTION 2

Heptode

Characteristics

  • Heater or filament voltage

    1.25 V

    Published nominal value

  • Heater or filament current

    53 mA

    Published nominal value