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Specialized - Switching Tube ·RelayControlSwitch

405A

Three-electrode inert-gas cold-cathode relay tube for communication, triggering, counting, switching, and control circuits. Gas ionization provides abrupt heaterless conduction.

Directly heatedCold cathodeCommon cathodeDissimilarSpecialized
Sections
1
Base
-
Socket code
UX4
Base pins
-
Nominal heater
-

Description

Three-electrode inert-gas-filled cold-cathode relay tube for communication, triggering, counting, switching, and control circuits.

Socket description

Medium-shell UX 4-contact

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base
-
Socket code
UX4
Base pins
-
Nominal heater voltage
-
Nominal heater current
-
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

RelayControlSwitch

X-ray radiationInterelectrode capacitances
Max cathode current
40 mA

Promoted fields mapped from printed maximum-rating and characteristic headings; additional published values preserved in parameter rows.

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

2026 Western Electric 400s

Published operating points and test conditions from this source.

SECTION 1

RelayControlSwitch

Characteristic

  • Peak Anode Voltage

    165 volts

    Peak Anode Voltage ..... 165 volts

  • Average Cathode Current

    4 milliamperes

    Average Cathode Current . 4 40 milliamperes

  • Averaging Time

    1 second

    Averaging Time . 1 second

  • Ambient Temperature Limits

    -55 centigrade

    Ambient Temperature Limits . —55 to 85 centigrade

  • Starter Breakdown Voltage*

    67 volts

    Starter Breakdown Voltage* . 67 75 89 volts

  • Starter Voltage Drop at

    10 amperes

    Starter Voltage Drop at 10 m:ll:amperes 52 60 74 volts

  • Anode Voltage Drop at

    10 milliamperes

    Anode Voltage Drop at 10 milliamperes. 66 75 W volts

  • Required Transfer Current at

    130 microamperes

    Required Transfer Current at 130 Anode Vo!ts (D C ) 50 . microamperes

Other

  • Peak Inverse Anode Current

    1 milliampere

    Peak Inverse Anode Current 1 milliampere