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

6J8G

Triode-heptode frequency changer for superheterodyne receivers. The triode serves as local oscillator while the heptode mixer provides very high plate resistance for strong isolation at the converter output.

Directly heatedCold cathodeCommon cathodeDissimilar
Sections
2
Base
8H
Socket code
IO
Base pins
8
Nominal heater
6.3 V / 300 mA

Description

Triode-heptode converter combining an oscillator triode and pentagrid mixer with a common cathode for frequency-conversion service.

Socket description

International Octal

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base
8H
Socket code
IO
Base pins
8
Nominal heater voltage
6.3 V
Nominal heater current
300 mA
Parallel heater voltage
-
Parallel heater current
-
Series capable
No

8H - 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
10600 Ω
Transconductance
0.0016 S
Amplification factor
17
Max plate voltage
300 V

Published maximum ratings, characteristics, operating conditions and capacitances reviewed.

Section 2

Heptode

X-ray radiationInterelectrode capacitances
Plate resistance
2500000 Ω
Max plate voltage
300 V
Max screen voltage
100 V

Published maximum ratings, characteristics, operating conditions and capacitances reviewed.

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

1937 Raytheon Radio Receiving Tubes

Published operating points and test conditions from this source.

SECTION 2

Heptode

Other

  • Maximum plate voltage

    250 V

    Published datasheet rating

  • Maximum screen voltage

    100 V

    Published datasheet rating

  • Plate voltage

    250 V

    ClassA

  • Screen voltage

    100 V

    ClassA

  • Screen current

    2.8 mA

    ClassA

  • Maximum triode plate supply voltage

    250 V

    Oscillator TriodeSection

  • Mixer plate voltage

    250 V

    HeptodeSection

  • Mixer screen voltage

    100 V

    HeptodeSection

  • Oscillator plate voltage

    250 V

    TriodeSection

  • Mixer screen current

    2.8 mA

    HeptodeSection

Characteristic

  • Plate resistance

    4000000 ohm

    Published datasheet characteristic

  • Transconductance

    290 µS

    Published datasheet characteristic

  • Heater voltage

    6.3 V

    Published heater rating

  • Heater current

    300 mA

    Published heater rating

  • Mixer plate resistance

    4000000 ohm

    HeptodeSection

  • Conversion transconductance

    290 µS

    Converter

Data set 02

1950 Sylvania

Published operating points and test conditions from this source.

SECTION 1

Triode

Characteristic

  • Plate Resistance

    10600 ohm

  • Transconductance

    1600 µS

  • Amplification Factor

    17

Other

  • Maximum Plate Voltage

    250 V

  • Plate Voltage

    100 V

    Triode oscillator section

SECTION 2

Heptode

Characteristic

  • Plate Resistance

    4000000 ohm

  • Conversion Conductance

    290 µS

    Heptode mixer; 250 V plate

Other

  • Maximum Plate Voltage

    250 V

  • Maximum Screen Voltage

    100 V

  • Plate Current

    1.3 mA

    Heptode mixer; 250 V plate

Data set 03

195X General Electric Essential Characteristics

Published operating points and test conditions from this source.

SECTION 2

Heptode

Other

  • Maximum plate voltage

    300 V

    Published handbook rating

  • Maximum screen voltage

    100 V

    Published handbook rating

  • Plate voltage

    250 V

    ClassA

  • Screen voltage

    100 V

    ClassA

  • Control-grid bias

    3 V

    ClassA

  • Plate current

    1.3 mA

    ClassA

  • Screen current

    3.5 mA

    ClassA

Characteristic

  • Plate resistance

    2500000 ohm

    Published handbook characteristic

  • Transconductance

    290 µS

    Published handbook characteristic

  • Heater voltage

    6.3 V

    Published heater rating

  • Heater current

    300 mA

    Published heater rating

Data set 04

1961 Tung Sol

Published operating points and test conditions from this source.

SECTION 1

Triode

Characteristic

  • Transconductance

    1600 uS

    Published operating/characteristic table

SECTION 2

Heptode

Characteristic

  • Transconductance

    1600 uS

    Published operating/characteristic table