6266

Special sharp-cutoff RF pentode designed for Class A high-frequency amplification. Its abrupt transfer characteristic provides fixed gain in RF signal stages rather than variable-mu automatic-gain-control operation.

Directly heatedCold cathodeCommon cathodeDissimilar

Sections: 1
Base: 7CM
Socket code: B7G
Base pins: 7
Nominal heater: 6.3 V / 175 mA

Description

Special sharp-cutoff RF pentode for Class-A high-frequency amplification.

Socket description

Miniature 7-contact

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base: 7CM
Socket code: B7G
Base pins: 7
Nominal heater voltage: 6.3 V
Nominal heater current: 175 mA
Parallel heater voltage: -
Parallel heater current: -
Series capable: No

7CM - Terminal pinout

Electrical assignments shared by every tube using this base designation.

Terminal	Section	Connection	Evidence
PIN1G1	A	G1 — Control Grid EIA chart transcription; manufacturer verification pending	Unverified EIA Base Connections, printed page 128, 7CM
PIN2K	A	K — Cathode EIA chart transcription; manufacturer verification pending	Unverified EIA Base Connections, printed page 128, 7CM
PIN3H	—	H — Heater EIA chart transcription; manufacturer verification pending	Unverified EIA Base Connections, printed page 128, 7CM
PIN4H	—	H — Heater EIA chart transcription; manufacturer verification pending	Unverified EIA Base Connections, printed page 128, 7CM
PIN5P	A	P — Plate (Anode) EIA chart transcription; manufacturer verification pending	Unverified EIA Base Connections, printed page 128, 7CM
PIN6G2	A	G2 — Screen Grid EIA chart transcription; manufacturer verification pending	Unverified EIA Base Connections, printed page 128, 7CM
PIN7G3	A	G3 — Suppressor GridGroup 7CM7 EIA chart transcription; manufacturer verification pending	Unverified EIA Base Connections, printed page 128, 7CM
PIN7IS	A	IS — Internal ScreenGroup 7CM7 EIA chart transcription; manufacturer verification pending	Unverified EIA Base Connections, printed page 128, 7CM

Section ratings

1 physical section, each with unique specifications.

Section 1

Pentode

X-ray radiationInterelectrode capacitances

Plate resistance: 1000000 Ω
Transconductance: 0.0046 S
Max plate voltage: 300 V
Max screen voltage: 150 V

Promoted from clearly identified printed ratings/characteristics; additional published operating points and capacitances 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

Capacitance

Input capacitance
5.2 pF
Section1
Output capacitance
4.4 pF
Section1
Grid-to-plate capacitance
0.004 pF
Section1

Other

Plate voltage
250 V
ClassA
Screen voltage
150 V
ClassA
Cathode resistor
100 Ω
ClassA
Plate current
7.4 mA
ClassA
Screen current
2.9 mA
ClassA

Characteristic

Plate resistance
1000000 Ω
ClassA
Transconductance
4600 µS
ClassA