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Voltage - Triode (single) ·Triode

B438

Low-filament-current directly heated receiving triode for battery-operated electronic service.

Directly heatedCold cathodeCommon cathodeDissimilar
Sections
1
Base
A
Socket code
B4
Base pins
4
Nominal heater
4 V / 50 mA

Description

B438 is listed in the supplied valve table as a triode. Published operating and characteristic values were transcribed from its target row.

Socket description

European 4-pin base

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base
A
Socket code
B4
Base pins
4
Nominal heater voltage
4 V
Nominal heater current
50 mA
Parallel heater voltage
-
Parallel heater current
-
Series capable
No

A - 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

Triode

X-ray radiationInterelectrode capacitances
Plate resistance
170000 Ω
Transconductance
0.002 S
Amplification factor
38

Published operating point, characteristic values and capacitance column reviewed.

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

1938 Philips Miniwatt Vacuum Tube Catalog

Published operating points and test conditions from this source.

SECTION 1

Triode

Characteristic

  • Plate resistance

    170000 ohm

    Published table characteristic

  • Heater/filament voltage

    4 V

    Published heater/filament rating

  • Heater/filament current

    50 mA

    Published heater/filament rating

Capacitance

  • Grid-to-plate capacitance

    0.32 pF

    Published table capacitance

Data set 02

1999 Philips 0-D

Published operating points and test conditions from this source.

SECTION 1

Triode

Other

  • Supply voltage

    200 V

    Published datasheet value

  • Anode load resistance

    320 kΩ

    Published datasheet value

  • Grid voltage

    -2.5 V

    Published datasheet value

  • Anode current

    0.2 mA

    Published datasheet value

  • Alternative anode load resistance

    1000 kΩ

    Published datasheet value

  • Alternative anode current

    0.05 mA

    Published datasheet value

Characteristics

  • Anode-grid capacitance

    4 pF

    Published datasheet value