12SJ7GT

Single-ended RF pentode designed for amplifier or anode-bend detector service in AC/DC equipment. Its ability to serve as a detector supplements its primary fixed-gain signal-amplifier function.

Directly heatedCold cathodeCommon cathodeDissimilar

Sections: 1
Base: 8N
Socket code: IO
Base pins: 8
Nominal heater: 12.6 V / 150 mA

Description

Single-ended RF pentode for amplifier or anode-bend detector service in AC/DC equipment.

Socket description

International Octal

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base: 8N
Socket code: IO
Base pins: 8
Nominal heater voltage: 12.6 V
Nominal heater current: 150 mA
Parallel heater voltage: -
Parallel heater current: -
Series capable: No

8N - Terminal pinout

Electrical assignments shared by every tube using this base designation.

Terminal	Section	Connection	Evidence
PIN1SH	A	SH — Internal Shield EIA transcription; independent manufacturer confirmation pending	Unverified EIA Base Connections, printed page 129, 8N
PIN2H	—	H — Heater EIA transcription; independent manufacturer confirmation pending	Unverified EIA Base Connections, printed page 129, 8N
PIN3G3	A	G3 — Suppressor Grid EIA transcription; independent manufacturer confirmation pending	Unverified EIA Base Connections, printed page 129, 8N
PIN4G1	A	G1 — Control Grid EIA transcription; independent manufacturer confirmation pending	Unverified EIA Base Connections, printed page 129, 8N
PIN5K	A	K — Cathode EIA transcription; independent manufacturer confirmation pending	Unverified EIA Base Connections, printed page 129, 8N
PIN6G2	A	G2 — Screen Grid EIA transcription; independent manufacturer confirmation pending	Unverified EIA Base Connections, printed page 129, 8N
PIN7H	—	H — Heater EIA transcription; independent manufacturer confirmation pending	Unverified EIA Base Connections, printed page 129, 8N
PIN8P	A	P — Plate (Anode) EIA transcription; independent manufacturer confirmation pending	Unverified EIA Base Connections, printed page 129, 8N

Section ratings

1 physical section, each with unique specifications.

Section 1

Pentode

X-ray radiationInterelectrode capacitances

Plate resistance: 1000000 Ω
Transconductance: 0.00165 S
Max plate voltage: 300 V
Max screen voltage: 150 V

Promoted from printed maximum/characteristic columns; additional published values retained in TUBE_SECTION_PARAMETER.

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

195X General Electric Essential Characteristics

Published operating points and test conditions from this source.

SECTION 1

Pentode

Other

Plate voltage
250 V
ClassA;PentodeConnection
Screen voltage
100 V
ClassA;PentodeConnection
Control-grid voltage
-3 V
ClassA;PentodeConnection
Plate current
3 mA
ClassA;PentodeConnection
Screen current
0.8 mA
ClassA;PentodeConnection
Plate voltage
250 V
ClassA;TriodeConnection
Control-grid voltage
-8.5 V
ClassA;TriodeConnection
Plate current
9.2 mA
ClassA;TriodeConnection

Characteristic

Plate resistance
1000000 Ω
PentodeConnection
Transconductance
1650 µS
PentodeConnection
Plate resistance
7600 Ω
TriodeConnection
Transconductance
2500 µS
TriodeConnection
Amplification factor
19
TriodeConnection

Data set 02

1961 Ferranti Technical Handbook

Published operating points and test conditions from this source.

SECTION 1

Pentode

Application

Application
RF amplifier / anode-bend detector