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277A

Gas-filled grid-controlled thyratron for switching, controlled-rectifier, relay, motor-control, oscillator, or pulse service as documented by the manufacturer.

Directly heatedCold cathodeCommon cathodeDissimilarSpecialized

Sections: 1
Base: -
Socket code: B5
Base pins: 5
Nominal heater: 5 V / 2 A

Description

Argon-filled trigger/relay triode with indirectly heated cathode.

Socket description

European 5-pin base

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base: -
Socket code: B5
Base pins: 5
Nominal heater voltage: 5 V
Nominal heater current: 2 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

1 physical section, each with unique specifications.

Section 1

Thyratron

X-ray radiationInterelectrode capacitances

Max cathode current: 500 mA
Rectifier forward voltage drop: 20 V
Rectifier max heater-cathode voltage: 12 V

Conducting drop 10–20 V.

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

1933 Western Electric Tubes

Published operating points and test conditions from this source.

SECTION 1

Thyratron

Characteristic

Anode-cathode conducting drop
10 V
Published datasheet value

Other

Maximum instantaneous space current
500 mA
Published datasheet value

Data set 02

2026 Western Electric 200s

Published operating points and test conditions from this source.

SECTION 1

Thyratron

Other

AnodeCathodePotentialDrop
10 to 20 V
Conducting
MaximumInstantaneousSpaceCurrent
500 mA
MaximumAnodeControlElectrodePotential
350 V