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Voltage Pentode ·Pentode

UF42

High-slope RF pentode for series-heater equipment. Manufacturer data specify approximately 8.5 mA/V transconductance at the published operating point and identify RF/IF amplifier service in transformerless receiver circuits.

Directly heatedCold cathodeCommon cathodeDissimilar
Sections
1
Base
-
Socket code
B8A
Base pins
8
Nominal heater
21 V / 100 mA

Description

High-slope RF pentode for series-heater equipment, with 8.5 mA/V transconductance at its published operating point.

Socket description

Rimlock 8-contact

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base
-
Socket code
B8A
Base pins
8
Nominal heater voltage
21 V
Nominal heater current
100 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
300000 Ω
Transconductance
0.008 S
Max plate voltage
250 V
Max screen voltage
250 V
Max plate dissipation
2 W
Max screen dissipation
0.5 W
Max cathode current
15 mA

wide-band RF/IF pentode.

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

    170 V

  • Plate Current

    10 mA

  • Screen Current

    2.8 mA

  • Control Grid Voltage

    -2 V

Characteristic

  • Transconductance

    8500 µS

  • Plate Resistance

    200000 ohm

Data set 02

1957 Philips Receiving and Amplifying Tubes

Published operating points and test conditions from this source.

SECTION 1

Pentode

Other

  • Plate Voltage

    170 V

  • Plate Current

    10 mA

  • Screen Voltage

    170 V

  • Screen Current

    2.8 mA

Characteristic

  • Transconductance

    8000 µS

  • Plate Resistance

    300000 ohm

Data set 03

1963 Philips Electron Tubes Handbook V1

Published operating points and test conditions from this source.

SECTION 1

Pentode

Other

  • Plate voltage

    170 V

    RF/IF amplifier

  • Screen voltage

    170 V

    RF/IF amplifier

  • Plate current

    10 mA

    RF/IF amplifier

  • Screen current

    2.8 mA

    RF/IF amplifier

  • Maximum plate voltage

    250 V

  • Maximum screen voltage

    250 V

  • Maximum plate dissipation

    2 W

Characteristic

  • Transconductance

    8000 uS

  • Plate resistance

    0.3 Mohm

Data set 04

1999 Philips E-Z

Published operating points and test conditions from this source.

SECTION 1

Pentode

Characteristics

  • Capacitances Ca

    4.3 a

    Capacitances Ca = 4,3 pF