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Voltage Pentode - Remote Cutoff (single) ·Pentode

DF97

Miniature battery RF pentode for IF amplification, frequency conversion, and self-oscillating mixer service. Its 1.4 V, 25 mA filament provides economical converter operation for compact portable superheterodyne receivers.

Directly heatedCold cathodeCommon cathodeDissimilar
Sections
1
Base
-
Socket code
B7G
Base pins
7
Nominal heater
1.4 V / 25 mA

Description

The Mullard DF97 is a miniature RF pentode for IF amplification, frequency-changing, and self-oscillating mixer 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
1.4 V
Nominal heater current
25 mA
Parallel heater voltage
1.4 V
Parallel heater current
25 mA
Series capable
Yes

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

Pentode

X-ray radiationInterelectrode capacitances
Plate resistance
525000 Ω
Transconductance
0.00094 S
Amplification factor
20
Max plate voltage
120 V
Max screen voltage
90 V
Max plate dissipation
0.25 W
Max screen dissipation
0.15 W
Max cathode current
2.5 mA

Variable-mu IF pentode for battery receivers and multiplicative mixing.

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 Ferranti Technical Handbook

Published operating points and test conditions from this source.

SECTION 1

Pentode

Application

  • Application

    IF amplifier / frequency changer / self-oscillating mixer

Data set 02

1963 Mullard

Published operating points and test conditions from this source.

SECTION 1

Pentode

Characteristics

  • Filament Voltage

    1.4 V

  • Filament Current

    25 mA

  • Plate Voltage

    85 V

    Representative

  • Screen Voltage

    57 V

    Representative

  • Plate Current

    1.5 mA

    Representative

  • Screen Current

    0.595 mA

    Representative

  • Transconductance

    900 uS

    Representative

  • Plate Resistance

    525000 ohm

    Representative

  • Input Capacitance

    3.7 pF

    PentodeConnection

  • Output Capacitance

    7.5 pF

    PentodeConnection

  • Plate-Grid Capacitance

    0.01 pF

    Maximum; PentodeConnection

Other

  • Conversion Transconductance

    265 uS

    FrequencyChanger; Va=85V

  • Maximum Plate Voltage

    150 V

    Absolute

  • Maximum Screen Supply Voltage

    120 V

  • Maximum Screen Voltage

    90 V

  • Maximum Plate Dissipation

    0.25 W

  • Maximum Screen Dissipation

    0.15 W

  • Maximum Cathode Current

    2.5 mA

Data set 03

1963 Philips Electron Tubes Handbook V1

Published operating points and test conditions from this source.

SECTION 1

Pentode

Capacitance

  • Plate capacitance

    8.1 pF

  • Grid-to-plate capacitance

    - to 0.01 pF

Other

  • Plate voltage

    64 V

    IF amplifier

  • Screen voltage

    62 V

    IF amplifier

  • Plate current

    1.7 mA

    IF amplifier

  • Screen current

    0.7 mA

    IF amplifier

Characteristic

  • Transconductance

    940 uS

    IF amplifier

  • Series filament voltage

    1.3 V

Data set 04

1999 Philips 0-D

Published operating points and test conditions from this source.

SECTION 1

Pentode

Other

  • Parallel heater voltage

    1.4 V

    Published datasheet value

  • Series heater voltage

    1.3 V

    Published datasheet value

  • Anode voltage

    85 V

    Published datasheet value

  • Screen-grid voltage

    62 V

    Published datasheet value

  • Anode current

    1.7 mA

    Published datasheet value

  • Screen-grid current

    0.7 mA

    Published datasheet value

Characteristics

  • Transconductance

    940 µS

    Published datasheet value

  • Internal resistance

    0.45 MΩ

    Published datasheet value

  • Screen-grid amplification factor

    20

    Published datasheet value

  • Conversion transconductance

    265 µS

    Multiplicative mixing; oscillator voltage on g3

  • Triode-connected anode capacitance

    8.1 pF

    TriodeConnection

  • Triode-connected grid capacitance

    1.1 pF

    TriodeConnection

  • Pentode anode capacitance

    7.5 pF

    Published datasheet value

  • Pentode control-grid capacitance

    3.7 pF

    Published datasheet value

  • Anode-control-grid capacitance

    - to 0.01 pF

    Published datasheet value