7A7

Single-ended remote-cutoff RF pentode using Lock-In construction. Designed for radio-frequency amplifier service, it combines variable-gain operation with short-lead mechanical construction.

Directly heatedCold cathodeCommon cathodeDissimilar

Sections: 1
Base: 8V
Socket code: B8G
Base pins: 8
Nominal heater: 6.3 V / 300 mA

Description

A single-ended remote-cutoff RF pentode of Lock-In construction for radio-frequency amplifier service.

Socket description

Loctal 8-contact

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base: 8V
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

8V - Terminal pinout

Electrical assignments shared by every tube using this base designation.

Terminal	Section	Connection	Evidence
PIN1H	—	H — Heater EIA source transcription; manufacturer confirmation pending	Unverified EIA Base Connections, printed page 129, 8V
PIN2P	A	P — Plate (Anode) EIA source transcription; manufacturer confirmation pending	Unverified EIA Base Connections, printed page 129, 8V
PIN3G2	A	G2 — Screen Grid EIA source transcription; manufacturer confirmation pending	Unverified EIA Base Connections, printed page 129, 8V
PIN4G3	A	G3 — Suppressor Grid EIA source transcription; manufacturer confirmation pending	Unverified EIA Base Connections, printed page 129, 8V
PIN5IS	A	IS — Internal Screen EIA chart transcription; manufacturer verification pending	Unverified EIA Base Connections, printed page 129, 8V
PIN6G1	A	G1 — Control Grid EIA chart transcription; manufacturer verification pending	Unverified EIA Base Connections, printed page 129, 8V
PIN7K	A	K — Cathode EIA chart transcription; manufacturer verification pending	Unverified EIA Base Connections, printed page 129, 8V
PIN8H	—	H — Heater EIA chart transcription; manufacturer verification pending	Unverified EIA Base Connections, printed page 129, 8V

Section ratings

1 physical section, each with unique specifications.

Section 1

Pentode

X-ray radiationInterelectrode capacitances

Plate resistance: 120000 Ω
Transconductance: 0.002 S
Max plate voltage: 300 V
Max screen voltage: 125 V
Max plate dissipation: 4 W
Max screen dissipation: 0.4 W

Published handbook ratings and representative operating characteristics reviewed.

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

Pentode

Characteristics

Anode Voltage
250 V
Anode Current
8.6 mA
Screen Voltage
100 V
Screen Current
2 mA
Control Grid Voltage
-3 V
Cathode Bias Resistor
300 ohm
Control Grid Voltage for Low Transconductance
-35 V
Transconductance=0.005mA/V

Data set 02

195X General Electric Essential Characteristics

Published operating points and test conditions from this source.

SECTION 1

Pentode

Other

Maximum plate voltage
250 V
Published handbook rating
Maximum screen voltage
100 V
Published handbook rating
Plate voltage
250 V
ClassA
Screen voltage
100 V
ClassA
Control-grid bias
3 V
ClassA
Plate current
9.2 mA
ClassA
Screen current
2.6 mA
ClassA

Characteristic

Plate resistance
800000 ohm
Published handbook characteristic
Transconductance
2000 µS
Published handbook characteristic
Heater voltage
6.3 V
Published heater rating
Heater current
300 mA
Published heater rating

Data set 03

1961 Tung Sol

Published operating points and test conditions from this source.

SECTION 1

Pentode

Other

Heater voltage
6.3 V
Nominal
Heater current
300 mA
Nominal
Plate voltage
300 V
Typical operating conditions
Screen voltage
125 V
Typical operating conditions
Plate current
139.2 mA
Typical operating conditions