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Voltage Pentode - Sharp Cutoff (single) ·Pentode

DF92

Mullard miniature short-grid-base RF pentode for battery-operated equipment. Manufacturer documentation identifies RF/IF amplifier service, combining compact construction, low-power filament operation, and fixed-gain high-frequency performance.

Directly heatedCold cathodeCommon cathodeDissimilar
Sections
1
Base
-
Socket code
B7G
Base pins
7
Nominal heater
1.4 V / 50 mA

Description

The Mullard DF92 is a miniature short-grid-base RF pentode for battery-operated equipment.

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
50 mA
Parallel heater voltage
1.4 V
Parallel heater current
50 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
600000 Ω
Transconductance
0.001025 S
Max plate voltage
110 V
Max screen voltage
90 V
Max cathode current
6.5 mA

RF/IF pentode for battery sets.

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

1951 Mullard Valve and Service Manual

Published operating points and test conditions from this source.

SECTION 1

Pentode

Other

  • Plate Voltage

    90 V

  • Screen Voltage

    67.5 V

  • Plate Current

    3.7 mA

  • Screen Current

    1.4 mA

Characteristic

  • Transconductance

    1000 µS

  • Plate Resistance

    500000 ohm

Data set 02

1961 Ferranti Technical Handbook

Published operating points and test conditions from this source.

SECTION 1

Pentode

Application

  • Application

    RF amplifier

Data set 03

1963 Mullard

Published operating points and test conditions from this source.

SECTION 1

Pentode

Characteristics

  • Filament Voltage

    1.4 V

    DCOnly

  • Filament Current

    50 mA

    DCOnly

  • Plate Voltage

    90 V

  • Screen Voltage

    67.5 V

  • Plate Current

    3.7 mA

  • Screen Current

    1.4 mA

  • Transconductance

    1000 uS

  • Plate Resistance

    500000 ohm

  • Input Capacitance

    3.6 pF

  • Output Capacitance

    7.5 pF

  • Plate-Grid Capacitance

    0.01 pF

    Maximum

Other

  • Maximum Plate Voltage

    90 V

  • Maximum Screen Voltage

    70 V

  • Maximum Cathode Current

    6 mA

Data set 04

1963 Philips Electron Tubes Handbook V1

Published operating points and test conditions from this source.

SECTION 1

Pentode

Capacitance

  • Plate capacitance

    7.5 pF

  • Grid-to-plate capacitance

    - to 0.008 pF

Other

  • Plate voltage

    90 V

    RF/IF amplifier

  • Screen voltage

    67.5 V

    RF/IF amplifier

  • Plate current

    2.9 mA

    RF/IF amplifier

  • Screen current

    1.2 mA

    RF/IF amplifier

Characteristic

  • Transconductance

    925 uS

    RF/IF amplifier

  • Plate resistance

    0.6 Mohm

Data set 05

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

    1.35 V

    Published datasheet value

  • Anode voltage

    90 V

    Published datasheet value

  • Screen-grid voltage

    67.5 V

    Published datasheet value

  • Anode current

    2.9 mA

    Published datasheet value

  • Screen-grid current

    1.2 mA

    Published datasheet value

Characteristics

  • Transconductance

    925 µS

    Published datasheet value

  • Internal resistance

    0.6 MΩ

    Published datasheet value

  • Alternative transconductance

    1025 µS

    Va=90V; Vg2=90V

  • Alternative internal resistance

    0.35 MΩ

    Va=90V; Vg2=90V

  • Anode capacitance

    1.5 pF

    Published datasheet value

  • Grid capacitance

    3.6 pF

    Published datasheet value

  • Anode-control-grid capacitance

    - to 0.008 pF

    Published datasheet value