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Voltage Pentode - Remote Cutoff (single) ·Pentode

EF41

Variable-mu voltage-amplifier pentode designed for RF and IF stages with automatic gain control. Its extended characteristic provides controlled receiver gain while maintaining useful high-frequency amplification.

Directly heatedCold cathodeCommon cathodeDissimilar
Sections
1
Base
RIMLOCK
Socket code
B8A
Base pins
8
Nominal heater
6.3 V / 200 mA

Description

Variable-mu voltage-amplifier pentode for RF and IF stages with automatic gain control.

Socket description

Rimlock 8-contact

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base
RIMLOCK
Socket code
B8A
Base pins
8
Nominal heater voltage
6.3 V
Nominal heater current
200 mA
Parallel heater voltage
-
Parallel heater current
-
Series capable
No

RIMLOCK - 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
2000000 Ω
Transconductance
0.0022 S
Max plate voltage
300 V
Max screen voltage
125 V
Max plate dissipation
1 W
Max screen dissipation
0.4 W
Max cathode current
15 mA

Published ratings/characteristics promoted from the approved source.

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

Characteristics

  • Cutoff characteristic

    Variable-mu

Data set 02

1953 La Radiotechnique

Published operating points and test conditions from this source.

SECTION 1

Pentode

Other

  • HeaterVoltageNominal

    6.3 V

    Nominal

  • HeaterCurrentNominal

    200 mA

    Nominal

  • Maximum Plate Voltage

    300 V

  • Maximum Screen Voltage

    250 V

  • Maximum Plate Dissipation

    1 W

Characteristic

  • Transconductance

    2200 µS

    Typical

  • Amplification Factor

    4400

    Typical

  • Plate Resistance

    2000000 ohm

    Typical

Data set 03

1958 Brimar Radio Valve No 7

Published operating points and test conditions from this source.

SECTION 1

Pentode

Characteristic

  • Heater Voltage

    6.3 V

  • Heater Current

    200 mA

Data set 04

1963 Philips Electron Tubes Handbook V1a

Published operating points and test conditions from this source.

SECTION 1

Pentode

Characteristic

  • Heater voltage

    6.3 V

    Published heater rating

  • Heater current

    200 mA

    Published heater rating

Other

  • Plate voltage

    250 V

    RForIFAmplifier

  • Grid bias

    -2.5 V

    RForIFAmplifier

  • Plate current

    6 mA

    RForIFAmplifier

  • Maximum plate voltage

    300 V

    Published limit

  • Maximum plate dissipation

    2 W

    Published limit

  • Maximum screen voltage

    300 V

    Published limit

Data set 05

1967 Mullard Receiving Tubes for Maintenance

Published operating points and test conditions from this source.

SECTION 1

Pentode

Other

  • Plate voltage

    250 V

    RFOrIFAmplifier

  • Screen-grid resistor

    90 kOhm

    RFOrIFAmplifier

  • Cathode resistor

    325 Ohm

    RFOrIFAmplifier

  • Control-grid voltage

    -2.5 V

    RFOrIFAmplifier

  • Plate current

    6 mA

    RFOrIFAmplifier

  • Screen-grid current

    1.7 mA

    RFOrIFAmplifier

  • Transconductance

    2.2 mA/V

    RFOrIFAmplifier

  • Maximum plate voltage

    300 V

  • Maximum plate dissipation

    2 W

  • Maximum screen-grid voltage

    125 V

    Ia=6mA

  • Maximum screen-grid dissipation

    0.3 W

  • Maximum cathode current

    10 mA

Capacitance

  • Input capacitance

    4.7 pF

  • Output capacitance

    8 pF

Data set 06

1968 Mazda Belvu

Published operating points and test conditions from this source.

SECTION 1

Pentode

Other

  • HeaterVoltageNominal

    6.3 V

    Nominal

  • HeaterCurrentNominal

    200 mA

    Nominal

  • Maximum Plate Voltage

    300 V

  • Maximum Screen Voltage

    250 V

  • Maximum Plate Dissipation

    1 W

  • Maximum Screen Dissipation

    0.4 W

  • Maximum Cathode Current

    15 mA

Characteristic

  • Transconductance

    2200 µS

    Typical

  • Amplification Factor

    4400

    Typical

  • Plate Resistance

    2000000 ohm

    Typical

Data set 07

1999 Philips E-Z

Published operating points and test conditions from this source.

SECTION 1

Pentode

Characteristics

  • Heater voltage

    6.3 V

  • Heater current

    200 mA

  • Typical plate voltage

    250 V

    Uncontrolled

  • Typical screen voltage

    100 V

    Uncontrolled

  • Typical plate current

    6 mA

    Uncontrolled

  • Transconductance

    2200 uS

    Uncontrolled

  • Plate resistance

    1.1 Mohm

    Uncontrolled

  • Screen-grid amplification factor

    18

Other

  • Maximum no-current plate voltage

    550 V

  • Maximum plate voltage

    300 V

Capacitance

  • Plate capacitance

    5.9 pF

  • Grid input capacitance

    5.3 pF

  • Plate-grid capacitance maximum

    0.002 pF

  • Grid-heater capacitance maximum

    0.05 pF