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Voltage - Dual Triode (dissimilar) ·Triode-Triode

3FW7

Medium-mu dual triode designed for VHF television and FM tuner frequency conversion, with one section serving as the local oscillator and the other as the mixer.

Directly heatedCold cathodeCommon cathodeDissimilar
Sections
2
Base
-
Socket code
B9A
Base pins
9
Nominal heater
3.5 V / 600 mA

Description

Medium-mu dual triode; section 1 oscillator and section 2 mixer for VHF TV/FM tuners.

Socket description

Small-button Noval 9-contact

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base
-
Socket code
B9A
Base pins
9
Nominal heater voltage
3.5 V
Nominal heater current
600 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

2 physical sections, each with unique specifications.

Section 1

Triode

X-ray radiationInterelectrode capacitances
Plate resistance
6000 Ω
Transconductance
0.006 S
Amplification factor
36
Max plate voltage
150 V
Max cathode current
20 mA

Oscillator section; separately published Unit 1 characteristics.

Section 2

Triode

X-ray radiationInterelectrode capacitances
Plate resistance
3800 Ω
Transconductance
0.0095 S
Amplification factor
36
Max plate voltage
150 V
Max cathode current
20 mA

Mixer section; separately published Unit 2 characteristics.

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

1982 Toshiba

Published operating points and test conditions from this source.

SECTION 1

Triode

Other

  • Plate Voltage

    20 V

    ClassA1

  • Grid Voltage

    -1 V

    ClassA1

  • Plate Current

    7 mA

    ClassA1

Capacitance

  • Grid-to-Plate Capacitance

    1.6 pF

    Section1

SECTION 2

Triode

Other

  • Plate Voltage

    0 V

    ClassA1

  • Grid Voltage

    -1 V

    ClassA1

  • Plate Current

    9 mA

    ClassA1

Capacitance

  • Grid-to-Plate Capacitance

    1.5 pF

    Section2