3BC6

Sharp-cutoff miniature RF pentode for Class-A high-frequency amplification, also specified for triode-connected operation.

Directly heatedCold cathodeCommon cathodeDissimilar

Sections: 1
Base: 7BD
Socket code: B7G
Base pins: 7
Nominal heater: 3.15 V / 600 mA

Description

Sharp-cutoff RF pentode for Class A amplification; also specified in triode connection.

Socket description

Miniature 7-contact

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base: 7BD
Socket code: B7G
Base pins: 7
Nominal heater voltage: 3.15 V
Nominal heater current: 600 mA
Parallel heater voltage: -
Parallel heater current: -
Series capable: No

7BD - Terminal pinout

Electrical assignments shared by every tube using this base designation.

Terminal	Section	Connection	Evidence
PIN1G1	A	G1 — Control Grid EIA transcription; manufacturer confirmation pending	Unverified EIA Base Connections, printed page 128, 7BD
PIN2G3	A	G3 — Suppressor GridGroup 7BD2 EIA transcription; manufacturer confirmation pending	Unverified EIA Base Connections, printed page 128, 7BD
PIN2IS	A	IS — Internal ScreenGroup 7BD2 EIA transcription; manufacturer confirmation pending	Unverified EIA Base Connections, printed page 128, 7BD
PIN2K	A	K — CathodeGroup 7BD2 EIA transcription; manufacturer confirmation pending	Unverified EIA Base Connections, printed page 128, 7BD
PIN3H	—	H — Heater EIA transcription; manufacturer confirmation pending	Unverified EIA Base Connections, printed page 128, 7BD
PIN4H	—	H — Heater EIA transcription; manufacturer confirmation pending	Unverified EIA Base Connections, printed page 128, 7BD
PIN5P	A	P — Plate (Anode) EIA chart transcription; manufacturer confirmation pending	Unverified EIA Base Connections, printed page 128, 7BD
PIN6G2	A	G2 — Screen Grid EIA chart transcription; manufacturer confirmation pending	Unverified EIA Base Connections, printed page 128, 7BD
PIN7G3	A	G3 — Suppressor GridGroup 7BD7 EIA chart transcription; manufacturer confirmation pending	Unverified EIA Base Connections, printed page 128, 7BD
PIN7IS	A	IS — Internal ScreenGroup 7BD7 EIA chart transcription; manufacturer confirmation pending	Unverified EIA Base Connections, printed page 128, 7BD
PIN7K	A	K — CathodeGroup 7BD7 EIA chart transcription; manufacturer confirmation pending	Unverified EIA Base Connections, printed page 128, 7BD

Section ratings

1 physical section, each with unique specifications.

Section 1

Pentode

X-ray radiationInterelectrode capacitances

Plate resistance: 800000 Ω
Transconductance: 0.0057 S
Max plate voltage: 300 V
Max screen voltage: 150 V

GE essential characteristics: 3BC6 indirectly heated 3.15 V, 0.6 A sharp-cutoff RF pentode for Class A amplifier operation. Maximum plate voltage 300 V and screen voltage 150 V. Published typical pentode condition at anode 250 V, screen 150 V with 180-ohm cathode bias resistor: plate current 7.5 mA, screen current 2.1 mA, transconductance 5700 µmhos (0.0057 S), approximate plate resistance 800 kΩ. Optional triode-connected use ties screen to plate; this is not a separate physical section. Values promoted are characteristics at this operating point, not absolute maximums.

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
Screen-grid voltage
150 V
ClassA
Grid No.1 bias
Rk=180 V
ClassA
Plate current
7.5 mA
ClassA
Screen-grid current
2.1 mA
ClassA
Plate resistance
800000 ohm
ClassA
Transconductance
5700 uS
ClassA
Plate voltage
125 V
ClassA
Screen-grid voltage
125 V
ClassA
Grid No.1 bias
Rk=100 V
ClassA
Plate current
8 mA
ClassA
Screen-grid current
2.4 mA
ClassA
Plate resistance
500000 ohm
ClassA
Transconductance
6100 uS
ClassA
Plate voltage
100 V
ClassA
Screen-grid voltage
100 V
ClassA
Grid No.1 bias
Rk=180 V
ClassA
Plate current
4.7 mA
ClassA
Screen-grid current
1.4 mA
ClassA
Plate resistance
600000 ohm
ClassA
Transconductance
4900 uS
ClassA
Plate voltage
250 V
ClassA;TriodeConnection

Characteristic

Plate resistance
9000 ohm
TriodeConnection
Transconductance
4400 uS
TriodeConnection
Amplification factor
40
TriodeConnection