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

7S7

Receiver oscillator-converter combining local oscillation and signal mixing for superheterodyne frequency conversion. Its multi-grid structure integrates the front-end frequency-changing functions in one envelope.

Directly heatedCold cathodeCommon cathodeDissimilar
Sections
2
Base
8BL
Socket code
B8G
Base pins
8
Nominal heater
6.3 V / 300 mA

Description

Loctal triode-heptode frequency changer with high conversion and efficient operation to about 100 MHz.

Socket description

Loctal 8-contact

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base
8BL
Socket code
B8G
Base pins
8
Nominal heater voltage
6.3 V
Nominal heater current
300 mA
Parallel heater voltage
-
Parallel heater current
-
Series capable
No

8BL - 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

Heptode

X-ray radiationInterelectrode capacitances
Plate resistance
1250000 Ω
Transconductance
0.00055 S
Max plate voltage
300 V
Max screen voltage
100 V
Max plate dissipation
0.6 W
Max screen dissipation
0.4 W
Max cathode current
14 mA
Rectifier max heater-cathode voltage
90 V

Published promoted fields populated by semantic section ownership; identical repeated sections compressed.

Section 2

Triode

X-ray radiationInterelectrode capacitances
Plate resistance
44000 Ω
Transconductance
0.0016 S
Amplification factor
70
Max plate voltage
175 V
Max plate dissipation
1 W
Max cathode current
14 mA
Rectifier max heater-cathode voltage
90 V

Published promoted fields populated by semantic section ownership; identical repeated sections compressed.

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

1948 Brimar Radio Valve Manual

Published operating points and test conditions from this source.

SECTION 1

Heptode

Other

  • Heptode Plate Voltage

    250 V

    HeptodeSection

  • Heptode Plate Current

    1.9 mA

    HeptodeSection

  • Heptode Screen Voltage

    100 V

    HeptodeSection

  • Heptode Screen Current

    3 mA

    HeptodeSection

  • Heptode Grid Voltage

    -2 V

    HeptodeSection

Characteristic

  • Heptode Plate Resistance

    1.25 Mohm

    HeptodeSection

  • Conversion Conductance

    530 µS

    HeptodeSection

SECTION 2

Triode

Other

  • Triode Supply Voltage

    250 V

    TriodeSection

  • Triode Plate Voltage

    150 V

    TriodeSection

  • Triode Plate Current

    5 mA

    TriodeSection

Characteristic

  • Maximum Operating Frequency

    100 MHz

Data set 02

1958 Brimar Radio Valve No 7

Published operating points and test conditions from this source.

SECTION 1

Heptode

Application

  • Application

    Frequency changer / mixer

Other

  • Maximum operating frequency

    100 MHz

SECTION 2

Triode

Application

  • Application

    Oscillator

Data set 03

195X General Electric Essential Characteristics

Published operating points and test conditions from this source.

SECTION 1

Heptode

Other

  • Plate voltage

    250 V

    Converter

  • Screen-grid voltage

    100 V

    Converter

  • Grid voltage

    -2 V

    Converter

  • Plate current

    1.8 mA

    Converter

  • Screen-grid current

    3 mA

    Converter

Characteristic

  • Plate resistance

    1250000 ohm

    Converter

  • Conversion transconductance

    525 uS

    Converter

SECTION 2

Triode

Other

  • Oscillator plate supply voltage

    250 V

    Converter;OscillatorSection

  • Oscillator plate series resistor

    20000 ohm

    Converter;OscillatorSection

  • Oscillator plate current

    5 mA

    Converter;OscillatorSection

  • Oscillator grid current

    0.4 mA

    Converter;OscillatorSection

  • Oscillator grid resistor

    50000 ohm

    Converter;OscillatorSection

Data set 04

1961 Ferranti Technical Handbook

Published operating points and test conditions from this source.

SECTION 1

Heptode

Other

  • Plate Voltage

    250 V

    FrequencyChanger

  • Screen Voltage

    100 V

    FrequencyChanger

  • Plate Current

    1.8 mA

    FrequencyChanger

  • Screen Current

    3 mA

    FrequencyChanger

Characteristics

  • Conversion Transconductance

    525 uS

    FrequencyChanger

SECTION 2

Triode

Characteristics

  • Plate Voltage

    100 V

  • Plate Current

    6.5 mA

  • Transconductance

    1650 uS

  • Plate Resistance

    11000 ohm

  • Amplification Factor

    18 ratio

Data set 05

1961 Tung Sol

Published operating points and test conditions from this source.

SECTION 1

Heptode

Characteristic

  • Conversion Transconductance

    550 uS

    Section1

SECTION 2

Triode

Characteristic

  • TriodeTransconductance

    1600 uS

    Section2