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Voltage Pentode - High Frequency (single) ·Pentode

EF70

Subminiature high-slope RF pentode with specialized suppressor-grid arrangement and internal suppressor diode for compact high-frequency circuitry.

Directly heatedCold cathodeCommon cathodeDissimilar
Sections
1
Base
-
Socket code
WIRE8
Base pins
8
Nominal heater
6.3 V / 200 mA

Description

The Mullard EF70 is a subminiature high-slope RF pentode with short suppressor-grid base and internal suppressor diode.

Socket description

Subminiature all-glass 8-wire lead family

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base
-
Socket code
WIRE8
Base pins
8
Nominal heater voltage
6.3 V
Nominal heater current
200 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

Pentode

X-ray radiationInterelectrode capacitances
Plate resistance
100000 Ω
Transconductance
0.0025 S
Max plate voltage
175 V
Max screen voltage
175 V
Max plate dissipation
0.75 W
Max screen dissipation
0.4 W

Published ratings and characteristics promoted from the supplied Brimar 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

1958 Mullard Receiving Tubes

Published operating points and test conditions from this source.

SECTION 1

Pentode

Characteristic

  • Heater Voltage

    6.3 V

  • Heater Current

    200 mA

Data set 02

1963 Mullard

Published operating points and test conditions from this source.

SECTION 1

Pentode

Characteristics

  • Heater Voltage

    6.3 V

  • Heater Current

    200 mA

  • Plate Voltage

    100 V

  • Screen Voltage

    100 V

  • Plate Current

    3 mA

  • Screen Current

    2.25 mA

  • Transconductance

    2500 uS

  • Plate Resistance

    100000 ohm

  • Plate-Grid Capacitance Maximum

    0.025 pF

    Shielded

  • Input Capacitance

    4.5 pF

    Shielded

  • Output Capacitance

    4.7 pF

    Shielded

  • Grid Voltage

    -2 V

  • Grid Voltage at PlateCurrent=100uA

    -8 V

Other

  • Maximum Plate Voltage

    175 V

  • Maximum Screen Voltage

    175 V

  • Maximum Plate Dissipation

    0.75 W

  • Maximum Screen Dissipation

    0.4 W

  • Maximum Plate Supply Voltage

    300 V

  • Maximum Screen Supply Voltage

    300 V