313CA

Three-electrode inert-gas cold-cathode control tube for relay and switching circuits. Its discharge provides abrupt controlled conduction without thermionic heating.

Directly heatedCold cathodeCommon cathodeDissimilarSpecialized

Sections: 1
Base: -
Socket code: UX4
Base pins: -
Nominal heater: -

Description

Three-electrode inert-gas-filled cold-cathode control tube.

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: 35 mA

Promoted fields audited from printed ratings/characteristics; remaining published values preserved as parameters.

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 300s

Published operating points and test conditions from this source.

SECTION 1

RelayControlSwitch

Characteristic

Average Cathode Current •
7 milliamperes
Average Cathode Current • 7 72 milliamperes
Peak Inverse Anode (Current (Note
2 milliamperes
Peak Inverse Anode (Current (Note 2). . . 5 milliamperes
Note
4 volts
Note 4: With 15 volts overvoltage (15 volts above starter breakdown voltage) with tube in total
Note
5 volt
Note 5: Negative anode voltage applied through 8000 ohms. Starter connected to anode through 100,000