400A

Western Electric heptode for multi-grid signal-processing and frequency-conversion service. Its electrode structure permits oscillator, mixer, or controlled-amplifier functions within one conventional receiving tube.

Directly heatedCold cathodeCommon cathodeDissimilar

Sections: 1
Base: -
Socket code: B7G
Base pins: 7
Nominal heater: 6.3 V / 200 mA

Description

Miniature pentagrid converter for frequency-conversion service.

Socket description

Miniature 7-contact

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base: -
Socket code: B7G
Base pins: 7
Nominal heater voltage: 6.3 V
Nominal heater current: 200 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

1 physical section, each with unique specifications.

Section 1

Heptode

X-ray radiationInterelectrode capacitances

Max plate voltage: 135 V
Max screen voltage: 135 V
Max cathode current: 7 mA

Promoted fields mapped from printed maximum-rating and characteristic headings; additional published values preserved in parameter rows.

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

2026 Western Electric 400s

Published operating points and test conditions from this source.

SECTION 1

Heptode

Characteristic

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136 volts
e biasesi asesasruncansar st 136 volts
Cathode Current ..c.viinvnonrense rm it eenserasesnns ceriraenenatans
7 milliamperes
Cathode Current ..c.viinvnonrense rm it eenserasesnns ceriraenenatans . 7 milliamperes
Filament Current ......... ehrrauarrecesennus e areassassesersaannans
200 milliamperes
Filament Current ......... ehrrauarrecesennus e areassassesersaannans 200 milliamperes
Cathode Current .ivceivansesosrsnaasnnannanns Chsrresasatnrassanaere
2.7 milliamperes
Cathode Current .ivceivansesosrsnaasnnannanns Chsrresasatnrassanaere 2.7 milliamperes
Conversion Transconductante ...veeesrcecsncsn verreerasana rerasseunn
230 micromhos
Conversion Transconductante ...veeesrcecsncsn verreerasana rerasseunn 230 micromhos