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Voltage Triode Pentode ·Diode-Pentode-Triode

1D8GT

Directly heated diode-triode-power-pentode combination for battery receivers; the pentode provides low-power audio output while the diode and triode handle signal functions.

Directly heatedCold cathodeCommon cathodeDissimilar
Sections
3
Base
8AJ
Socket code
IO
Base pins
8
Nominal heater
1.4 V / 100 mA

Description

Directly heated combination tube containing a diode, a triode, and a power-amplifier pentode.

Socket description

International Octal

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base
8AJ
Socket code
IO
Base pins
8
Nominal heater voltage
1.4 V
Nominal heater current
100 mA
Parallel heater voltage
-
Parallel heater current
-
Series capable
No

8AJ - Terminal pinout

Electrical assignments shared by every tube using this base designation.

No verified pinout is recorded for this base designation.

Section ratings

3 physical sections, each with unique specifications.

Section 1

Diode

X-ray radiationInterelectrode capacitances

No fixed ratings are recorded for this section.

Detector diode at negative end of common filament; independent of triode and pentode except common filament.

Section 2

Triode

X-ray radiationInterelectrode capacitances
Plate resistance
77000 Ω
Transconductance
0.000325 S
Amplification factor
25
Max plate voltage
110 V

Promoted characteristics use first listed Class A1 condition.

Section 3

Pentode

X-ray radiationInterelectrode capacitances
Plate resistance
300000 Ω
Transconductance
0.00065 S
Max plate voltage
110 V
Max screen voltage
110 V
Max cathode current
6 mA

Promoted characteristics use first listed Class A1 pentode condition.

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 2

Triode

Other

  • Maximum plate voltage

    110 V

  • Plate voltage

    90 V

    ClassA

  • Control-grid voltage

    0 V

    ClassA

  • Plate current

    1.1 mA

    ClassA

  • Plate resistance

    43500 Ohm

    ClassA

  • Transconductance

    575 uS

    ClassA

  • Amplification factor

    25

    ClassA

SECTION 3

Pentode

Other

  • Maximum plate voltage

    110 V

  • Maximum screen-grid voltage

    110 V

  • Plate voltage

    90 V

    ClassA

  • Screen-grid voltage

    90 V

    ClassA

  • Control-grid voltage

    -9 V

    ClassA

  • Plate current

    5 mA

    ClassA

  • Screen-grid current

    1 mA

    ClassA

  • Plate resistance

    200000 Ohm

    ClassA

  • Transconductance

    925 uS

    ClassA

  • Load resistance

    12000 Ohm

    ClassA

  • Power output

    0.2 W

    ClassA

Data set 02

1961 Tung Sol

Published operating points and test conditions from this source.

SECTION 1

Diode

Characteristic

  • Minimum Diode Current

    0.5 mA

    DcApplied=40V

SECTION 2

Triode

Other

  • Filament Voltage

    1.4 V

    Nominal

  • Filament Current

    100 mA

    Nominal

  • Plate Voltage

    45 V

    ClassA1;Triode;PlateVoltage=45V

  • Grid Voltage

    0 V

    ClassA1;Triode;PlateVoltage=45V

  • Plate Current

    0.3 mA

    ClassA1;Triode;PlateVoltage=45V

  • Plate Voltage

    67.5 V

    ClassA1;Triode;PlateVoltage=67.5V

  • Grid Voltage

    0 V

    ClassA1;Triode;PlateVoltage=67.5V

  • Plate Current

    0.6 mA

    ClassA1;Triode;PlateVoltage=67.5V

  • Plate Voltage

    90 V

    ClassA1;Triode;PlateVoltage=90V

  • Grid Voltage

    0 V

    ClassA1;Triode;PlateVoltage=90V

  • Plate Current

    1.1 mA

    ClassA1;Triode;PlateVoltage=90V

Characteristic

  • Plate Resistance

    77000 ohm

    ClassA1;Triode;PlateVoltage=45V

  • Transconductance

    325 uS

    ClassA1;Triode;PlateVoltage=45V

  • Amplification Factor

    25

    ClassA1;Triode;PlateVoltage=45V

  • Plate Resistance

    55500 ohm

    ClassA1;Triode;PlateVoltage=67.5V

  • Transconductance

    450 uS

    ClassA1;Triode;PlateVoltage=67.5V

  • Amplification Factor

    25

    ClassA1;Triode;PlateVoltage=67.5V

  • Plate Resistance

    43500 ohm

    ClassA1;Triode;PlateVoltage=90V

  • Transconductance

    575 uS

    ClassA1;Triode;PlateVoltage=90V

  • Amplification Factor

    25

    ClassA1;Triode;PlateVoltage=90V

SECTION 3

Pentode

Other

  • Plate Voltage

    45 V

    ClassA1;Pentode;PlateVoltage=45V

  • Screen Voltage

    45 V

    ClassA1;Pentode;PlateVoltage=45V

  • Control Grid Voltage

    -4.5 V

    ClassA1;Pentode;PlateVoltage=45V

  • Plate Current

    1.6 mA

    ClassA1;Pentode;PlateVoltage=45V

  • Screen Current

    0.3 mA

    ClassA1;Pentode;PlateVoltage=45V

  • Load Resistance

    20000 ohm

    ClassA1;Pentode;PlateVoltage=45V

  • Total Harmonic Distortion

    10 %

    ClassA1;Pentode;PlateVoltage=45V

  • Power Output

    35 mW

    ClassA1;Pentode;PlateVoltage=45V

  • Plate Voltage

    62.5 V

    ClassA1;Pentode;PlateVoltage=62.5V

  • Screen Voltage

    62.5 V

    ClassA1;Pentode;PlateVoltage=62.5V

  • Control Grid Voltage

    -5 V

    ClassA1;Pentode;PlateVoltage=62.5V

  • Plate Current

    3.8 mA

    ClassA1;Pentode;PlateVoltage=62.5V

  • Screen Current

    0.8 mA

    ClassA1;Pentode;PlateVoltage=62.5V

  • Load Resistance

    16000 ohm

    ClassA1;Pentode;PlateVoltage=62.5V

  • Total Harmonic Distortion

    10 %

    ClassA1;Pentode;PlateVoltage=62.5V

  • Power Output

    90 mW

    ClassA1;Pentode;PlateVoltage=62.5V

  • Plate Voltage

    67.5 V

    ClassA1;Pentode;PlateVoltage=67.5V

  • Screen Voltage

    67.5 V

    ClassA1;Pentode;PlateVoltage=67.5V

  • Control Grid Voltage

    -6 V

    ClassA1;Pentode;PlateVoltage=67.5V

  • Plate Current

    3.8 mA

    ClassA1;Pentode;PlateVoltage=67.5V

  • Screen Current

    0.8 mA

    ClassA1;Pentode;PlateVoltage=67.5V

  • Load Resistance

    16000 ohm

    ClassA1;Pentode;PlateVoltage=67.5V

  • Total Harmonic Distortion

    10 %

    ClassA1;Pentode;PlateVoltage=67.5V

  • Power Output

    100 mW

    ClassA1;Pentode;PlateVoltage=67.5V

Characteristic

  • Plate Resistance

    300000 ohm

    ClassA1;Pentode;PlateVoltage=45V

  • Transconductance

    650 uS

    ClassA1;Pentode;PlateVoltage=45V

  • Plate Resistance

    200000 ohm

    ClassA1;Pentode;PlateVoltage=62.5V

  • Transconductance

    875 uS

    ClassA1;Pentode;PlateVoltage=62.5V

  • Plate Resistance

    200000 ohm

    ClassA1;Pentode;PlateVoltage=67.5V

  • Transconductance

    875 uS

    ClassA1;Pentode;PlateVoltage=67.5V