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Voltage Radio Detector Converter ·Pentode-Triode

8GX7

Medium-mu triode plus frame-grid pentode for VHF television-tuner oscillator and mixer service.

Directly heatedCold cathodeCommon cathodeDissimilar
Sections
2
Base
-
Socket code
B9A
Base pins
9
Nominal heater
7.7 V / 300 mA

Description

Medium-mu triode plus frame-grid pentode for VHF television tuner oscillator-mixer service.

Socket description

Small-button Noval 9-contact

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base
-
Socket code
B9A
Base pins
9
Nominal heater voltage
7.7 V
Nominal heater current
300 mA
Parallel heater voltage
-
Parallel heater current
-
Series capable
No

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
Max plate voltage
275 V

Triode section; published ratings and characteristics promoted where unambiguous.

Section 2

Pentode

X-ray radiationInterelectrode capacitances
Transconductance
0.011 S
Max plate voltage
275 V
Max screen voltage
275 V
Max screen dissipation
0.45 W

Pentode section; published ratings and characteristics promoted where unambiguous.

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

1965 Sylvania Electronic Tubes Vol3

Published operating points and test conditions from this source.

SECTION 1

Triode

Characteristic

  • Heater voltage

    7.7 V

    Rated heater condition

  • Heater current

    300 mA

    Rated heater condition

  • Plate Voltage

    125 V

    Plate Voltage .........., ..120 125 Volts

  • Grid I Voltage

    1 V

    Grid I Voltage .........., ...-- 1.0 Volts

  • 9-Pin Base Plato Resistance

    200000 ohm

    9-Pin Base Plato Resistance ........ I •..- 200000 Ohms

  • Plate Current

    8 mA

    Plate Current .........., •. 8.5 8.0 Ma.

Other

  • Voltage . . 4.2 5.6 6.3

    7.7 V

    Voltage . . 4.2 5.6 6.3 7.7 Volts Plato Voltage ...... 275 275 max. Volts

  • Cu,rent , , 0.60 0.45 0.40

    300 mA

    Cu,rent , , 0.60 0.45 0.40 0.30 Ampere Grid 2 Supply Voltage. . - 275 max. Volts

  • Grid to Plate

    1.2 pF

    Grid to Plate ............ •.............. 1.2 pf Grid 2 Dissipation ..... - 0.45 max. Watts

  • Input

    2.3 pF

    Input................. •.............. 2.3 pf Positive Grid I Voltage. . .0 0 max. Volts

  • Output

    1.9 pF

    Output................ •.............. 1.9 pf Negative Grid 1 Voltage . 40 40 max. Volts

  • Grid 1 to Plato

    0.005 pF

    Grid 1 to Plato .......... •............. 0.005 pf Grid 1 Circuit Resistance

  • Grid 1 to Grid 2

    1.6 pF

    Grid 1 to Grid 2 .......... •............... 1.6 pf Heater-Cathode Voltage:

SECTION 2

Pentode

Characteristic

  • Heater voltage

    7.7 V

    Rated heater condition

  • Heater current

    300 mA

    Rated heater condition