3FQ5A

Improved semi-remote-cutoff triode for VHF RF-amplifier service.

Directly heatedCold cathodeCommon cathodeDissimilar

Sections: 1
Base: -
Socket code: B7G
Base pins: 7
Nominal heater: 2.8 V / 450 mA

Description

Improved semi-remote-cutoff triode for VHF and RF amplifier service.

Socket description

Miniature 7-contact

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base: -
Socket code: B7G
Base pins: 7
Nominal heater voltage: 2.8 V
Nominal heater current: 450 mA
Parallel heater voltage: -
Parallel heater current: -
Series capable: No

Terminal pinout

Electrical assignments shared by every tube using this base designation.

No verified pinout is recorded for this base designation.

Section ratings

1 physical section, each with unique specifications.

Section 1

Triode

X-ray radiationInterelectrode capacitances

Plate resistance: 6300 Ω
Transconductance: 0.012 S
Amplification factor: 74
Max plate voltage: 200 V
Max plate dissipation: 2.5 W
Max cathode current: 22 mA

Promoted from clearly identified source values; additional cutoff, RF/IF, television, capacitance, and heater-condition data are 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

1961 Tung Sol

Published operating points and test conditions from this source.

SECTION 1

Triode

Capacitance

GRID TO PLATE
0.52 PF
Published datasheet value
INPUT: G TO (HtKk+i.s.tE.S.)
5 PF
Published datasheet value
OUTPUT: P TO (HtK+1.S5.+E.S.)
3.5 PF
Published datasheet value

Other

HEATER TO CATHODE
2.8 PF
Published datasheet value
MAX IMUM PLATE VOLTAGE
200 VOLTS
Published datasheet value
MAXIMUM DC CATHODE CURRENT
22 MA
Published datasheet value
MAX IMUM NEGATIVE GRID VOLTAGE
50 VOLTS
Published datasheet value
GRID VOLTAGE
-1.2 VOLTS
Published datasheet value
PLATE CURRENT
8.9 MA
Published datasheet value

Data set 02

1966 Tung Sol Electronic Tubes 1 of 4

Published operating points and test conditions from this source.

SECTION 1

Triode

Capacitance

Heater-to-cathode capacitance
2.5 pF
Section1

Other

Plate voltage
135 V
VHFRFAmplifier
Plate current
8.9 mA
VHFRFAmplifier
Application
Semi-remote-cutoff VHF/RF amplifier
Section1

Characteristic

Transconductance
12000 µS
Section1
Amplification factor
74
Section1
Plate resistance
6300 Ω
Section1
Heater warm-up time
11 s
Section1