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Rectifier - Full Wave ·Rectifier-Rectifier

U18

Directly heated full-wave rectifier with dual electrode system for higher-current supplies, designed for long life and stable emission while providing approximately 250 mA DC output.

Directly heatedCold cathodeCommon cathodeDissimilar
Sections
2
Base
-
Socket code
B4
Base pins
4
Nominal heater
4 V / 3.75 A

Description

A full-wave rectifying valve with a dual electrode system, designed for long life and constant emission at its rated filament voltage and output.

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
-
Socket code
B4
Base pins
4
Nominal heater voltage
4 V
Nominal heater current
3.75 A
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

2 physical sections, each with unique specifications.

Section 1

Rectifier

X-ray radiationInterelectrode capacitances
Rectifier peak inverse voltage
1400 V
Rectifier nominal output current
250 mA
Rectifier max heater-cathode voltage
0 V

Published ratings and characteristics promoted from the approved datasheet.

Section 2

Rectifier

X-ray radiationInterelectrode capacitances
Rectifier peak inverse voltage
1400 V
Rectifier nominal output current
250 mA
Rectifier max heater-cathode voltage
0 V

Physical rectifier section 2; identical section values duplicated per physical-section policy.

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

1937 Osram Valves

Published operating points and test conditions from this source.

SECTION 1

Rectifier

Other

  • Heater Voltage

    4 V

    Published datasheet value

  • Heater Current

    3.75 A

    Published datasheet value

  • Anode Voltage RMS

    500 V

    EachAnode

  • Rectified DC Current

    250 mA

    Published datasheet value

  • DC Output Voltage

    520 V

    At maximum rated AC input

Data set 02

193X Osram

Published operating points and test conditions from this source.

SECTION 1

Rectifier

Characteristic

  • Anode RMS voltage each anode

    500 V

    Published datasheet value

  • DC output voltage

    520 V

    Published datasheet value

Data set 03

1955 Marconi

Published operating points and test conditions from this source.

SECTION 1

Rectifier

Other

  • Heater/filament voltage

    4 V

  • Heater/filament current

    3.75 A

  • Peak inverse voltage

    1400 V

  • Nominal/maximum output current

    250 mA

Construction

  • Rectifier topology

    Bi-phase/full-wave