6749

Remote- or semi-remote-cutoff pentode designed for RF, IF, variable-mu, or controlled-gain amplifier service.

Directly heatedCold cathodeCommon cathodeDissimilar

Sections: 1
Base: 7BK
Socket code: B7G
Base pins: 7
Nominal heater: 6.3 V / 300 mA

Description

6749 is listed in the supplied receiving-tube handbook as a remote-cutoff RF pentode. The published heater/filament rating is 6.3 V at 0.3 A. Maximum ratings, representative operating characteristics, and available special-service data were captured from the supplied table.

Socket description

Miniature 7-contact

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base: 7BK
Socket code: B7G
Base pins: 7
Nominal heater voltage: 6.3 V
Nominal heater current: 300 mA
Parallel heater voltage: -
Parallel heater current: -
Series capable: No

7BK - Terminal pinout

Electrical assignments shared by every tube using this base designation.

Terminal	Section	Connection	Evidence
PIN1G1	A	G1 — Control Grid EIA chart transcription; independent manufacturer confirmation pending	Unverified EIA Base Connections, printed page 128, 7BK
PIN2G3	A	G3 — Suppressor GridGroup 7BK2 EIA chart transcription; independent manufacturer confirmation pending	Unverified EIA Base Connections, printed page 128, 7BK
PIN2IS	A	IS — Internal ScreenGroup 7BK2 EIA chart transcription; independent manufacturer confirmation pending	Unverified EIA Base Connections, printed page 128, 7BK
PIN3H	—	H — Heater EIA chart transcription; independent manufacturer confirmation pending	Unverified EIA Base Connections, printed page 128, 7BK
PIN4H	—	H — Heater EIA chart transcription; independent manufacturer confirmation pending	Unverified EIA Base Connections, printed page 128, 7BK
PIN5P	A	P — Plate (Anode) EIA chart transcription; independent manufacturer confirmation pending	Unverified EIA Base Connections, printed page 128, 7BK
PIN6G2	A	G2 — Screen Grid EIA chart transcription; independent manufacturer confirmation pending	Unverified EIA Base Connections, printed page 128, 7BK
PIN7K	A	K — Cathode EIA chart transcription; independent manufacturer confirmation pending	Unverified EIA Base Connections, printed page 128, 7BK

Section ratings

1 physical section, each with unique specifications.

Section 1

Pentode

X-ray radiationInterelectrode capacitances

Plate resistance: 1000000 Ω
Transconductance: 0.0044 S
Max plate voltage: 300 V
Max screen voltage: 150 V

Published maximum ratings, representative operating conditions, and available capacitance/rectifier data 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

195X General Electric Essential Characteristics

Published operating points and test conditions from this source.

SECTION 1

Pentode

Other

Maximum plate voltage
300 V
Published handbook rating
Maximum screen voltage
150 V
Published handbook rating
Plate voltage
250 V
ClassA
Screen voltage
100 V
ClassA
Plate current
11 mA
ClassA
Screen current
4.2 mA
ClassA
Alternate plate voltage
100 V
ClassA OperatingPoint2
Alternate screen voltage
100 V
ClassA OperatingPoint2
Alternate plate current
10.8 mA
ClassA OperatingPoint2
Alternate screen current
4.4 mA
ClassA OperatingPoint2

Characteristic

Plate resistance
1000000 ohm
Published handbook characteristic
Transconductance
4400 µS
Published handbook characteristic
Heater/filament voltage
6.3 V
Published heater/filament rating
Heater/filament current
300 mA
Published heater/filament rating
Alternate plate resistance
250000 ohm
ClassA OperatingPoint2
Alternate transconductance
4300 µS
ClassA OperatingPoint2

Capacitance

Input capacitance
5.5 pF
Published capacitance column
Output capacitance
5.5 pF
Published capacitance column
Grid-to-plate capacitance
0.0035 pF
Published capacitance column