8426A

Miniature sharp-cutoff pentode designed for industrial applications. Its compact fixed-gain construction supports professional signal-amplifier service where small size and dependable operation are important.

Directly heatedCold cathodeCommon cathodeDissimilar

Sections: 1
Base: 7BK
Socket code: B7G
Base pins: 7
Nominal heater: 12.6 V / 150 mA

Description

Miniature sharp-cutoff pentode for industrial applications.

Socket description

Miniature 7-contact

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base: 7BK
Socket code: B7G
Base pins: 7
Nominal heater voltage: 12.6 V
Nominal heater current: 150 mA
Parallel heater voltage: -
Parallel heater current: -
Series capable: No

7BK - Terminal pinout

Electrical assignments shared by every tube using this base designation.

Terminal	Section	Connection	Evidence
PIN1G1	A	G1 — Control Grid EIA chart transcription; independent manufacturer confirmation pending	Unverified EIA Base Connections, printed page 128, 7BK
PIN2G3	A	G3 — Suppressor GridGroup 7BK2 EIA chart transcription; independent manufacturer confirmation pending	Unverified EIA Base Connections, printed page 128, 7BK
PIN2IS	A	IS — Internal ScreenGroup 7BK2 EIA chart transcription; independent manufacturer confirmation pending	Unverified EIA Base Connections, printed page 128, 7BK
PIN3H	—	H — Heater EIA chart transcription; independent manufacturer confirmation pending	Unverified EIA Base Connections, printed page 128, 7BK
PIN4H	—	H — Heater EIA chart transcription; independent manufacturer confirmation pending	Unverified EIA Base Connections, printed page 128, 7BK
PIN5P	A	P — Plate (Anode) EIA chart transcription; independent manufacturer confirmation pending	Unverified EIA Base Connections, printed page 128, 7BK
PIN6G2	A	G2 — Screen Grid EIA chart transcription; independent manufacturer confirmation pending	Unverified EIA Base Connections, printed page 128, 7BK
PIN7K	A	K — Cathode EIA chart transcription; independent manufacturer confirmation pending	Unverified EIA Base Connections, printed page 128, 7BK

Section ratings

1 physical section, each with unique specifications.

Section 1

Pentode

X-ray radiationInterelectrode capacitances

Plate resistance: 1100000 Ω
Transconductance: 0.0062 S
Max plate voltage: 275 V
Max plate dissipation: 3.5 W
Max screen dissipation: 0.75 W

Pentode-connection characteristics promoted; triode-connection data retained as parameters.

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

1968 General Electric Co

Published operating points and test conditions from this source.

SECTION 1

Pentode

Other

HeaterOrFilamentVoltageNominal
12.6 V
HeaterOrFilamentCurrentNominal
150 mA
Maximum Plate Voltage
275 V
Maximum Plate Dissipation
3.5 W
Maximum Screen Dissipation
0.75 W

Characteristic

Plate Resistance
1100000 Ohm
PlateVoltage=250V;ScreenVoltage=150V
Transconductance
6200 uS
PlateVoltage=250V;ScreenVoltage=150V
TriodeConnectionAmplificationFactor
41
TriodeConnection