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Voltage - Dual Triode (similar) ·Triode-Triode

6BF7

General-purpose subminiature medium-mu double triode with separate cathode leads, intended for Class-A amplifier and related compact electronic applications.

Directly heatedCold cathodeCommon cathodeDissimilar

Sections: 2
Base: 8DG
Socket code: SUBMINIATURE8
Base pins: 8
Nominal heater: 6.3 V / 300 mA

Description

General-purpose subminiature double triode with separate cathode leads.

Socket description

Subminiature 8-lead base

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base: 8DG
Socket code: SUBMINIATURE8
Base pins: 8
Nominal heater voltage: 6.3 V
Nominal heater current: 300 mA
Parallel heater voltage: -
Parallel heater current: -
Series capable: No

8DG - Terminal pinout

Electrical assignments shared by every tube using this base designation.

Terminal	Section	Connection	Evidence
PIN12P	B	P — Plate (Anode) EIA source transcription; manufacturer confirmation pending	Unverified EIA Base Connections, printed page 129, 8DG
PIN22G1	B	G1 — Control Grid Original EIA label 2G1; manufacturer confirmation pending	Unverified EIA Base Connections, printed page 129, 8DG
PIN3H	—	H — Heater Original EIA label H; manufacturer confirmation pending	Unverified EIA Base Connections, printed page 129, 8DG
PIN42K	B	K — Cathode Original EIA label 2K; manufacturer confirmation pending	Unverified EIA Base Connections, printed page 129, 8DG
PIN51K	A	K — Cathode Original EIA label 1K; manufacturer confirmation pending	Unverified EIA Base Connections, printed page 129, 8DG
PIN6H	—	H — Heater Original EIA label H; manufacturer confirmation pending	Unverified EIA Base Connections, printed page 129, 8DG
PIN71G1	A	G1 — Control Grid Original EIA label 1G1; manufacturer confirmation pending	Unverified EIA Base Connections, printed page 129, 8DG
PIN81P	A	P — Plate (Anode) Original EIA label 1P; manufacturer confirmation pending	Unverified EIA Base Connections, printed page 129, 8DG

Section ratings

2 physical sections, each with unique specifications.

Section 1

Triode

X-ray radiationInterelectrode capacitances

Plate resistance: 7000 Ω
Transconductance: 0.0048 S
Amplification factor: 35
Max plate voltage: 250 V
Max plate dissipation: 2.5 W
Rectifier max heater-cathode voltage: 90 V

Published promoted fields populated semantically; identical repeated sections compressed where applicable.

Section 2

Triode

X-ray radiationInterelectrode capacitances

Plate resistance: 7000 Ω
Transconductance: 0.0048 S
Amplification factor: 35
Max plate voltage: 250 V
Max plate dissipation: 2.5 W

Physical triode restored under current one-row-per-physical-section policy.

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

Triode

Other

Plate voltage
100 V
ClassA; OperatingPoint1
Cathode resistor
100 ohm
ClassA; OperatingPoint1
Plate current
8 mA
ClassA; OperatingPoint1
Plate resistance
7000 ohm
ClassA; OperatingPoint1
Transconductance
4800 uS
ClassA; OperatingPoint1
Amplification factor
35
ClassA; OperatingPoint1

Characteristics

Input capacitance
2 pF
Output capacitance
1.6 pF
Section1
Grid-to-plate capacitance
1.5 pF

Data set 02

1961 Tung Sol

Published operating points and test conditions from this source.

SECTION 1

Triode

Characteristic

Amplification Factor
35
Typical
Transconductance
4800 uS
Typical

Data set 03

1966 Tung Sol Electronic Tubes 1 of 4

Published operating points and test conditions from this source.

SECTION 1

Triode

Capacitance

GRID TO PLATE (EACH SECTION)
5 µµf
Capacitances | GRID TO PLATE (EACH SECTION) 1.5 1..5 µµf

Characteristic

GRID TO GRID
0.009 µµf
Section 2 | GRID TO GRID 0.008 0.009 µµf
PLATE TO PLATE
0.75 µµf
Section 2 | PLATE TO PLATE 0.55 0.75 µµf

Other

HEATER VOLTAGE
6.3 V
Maximum Ratings | HEATER VOLTAGE 6.3 VOLTS
MAXIMUM HEATER —CATHODE VOLTAGE
90 V
Maximum Ratings | MAXIMUM HEATER —CATHODE VOLTAGE 90 VOLTS
MAXIMUM PLATE DISSIPATION (EACH SECTION)
1 W
Maximum Ratings | MAXIMUM PLATE DISSIPATION (EACH SECTION) 1.0 WATT
HEATER VOLTAGE
6.3 V
Typical Operating Conditions | HEATER VOLTAGE 6.3 voLTs
HEATER CURRENT O
3 A
Typical Operating Conditions | HEATER CURRENT O.3 AMP.
GRID VOLTAGE FOR
7.5 V
Typical Operating Conditions | GRID VOLTAGE FOR 10 µAMP. PLATE CURRENT —7.5 voLTs