Skip to main content
Tube Tinker — Electron Tube Database
Alternatives & variationsDownload PDF datasheet

Specialized - Thyratron ·Thyratron

NL740L

Industrial thyratron for grid-controlled rectifier and control service. Its heavy directly heated cathode supports substantial controlled discharge.

Directly heatedCold cathodeCommon cathodeDissimilarSpecialized
Sections
1
Base
-
Socket code
-
Base pins
-
Nominal heater
2.5 V / 10 A

Description

NL740L industrial thyratron for grid-controlled rectifier and control service.

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base
-
Socket code
-
Base pins
-
Nominal heater voltage
2.5 V
Nominal heater current
10 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
4 A

Gas/mercury-filled grid-controlled rectifier (thyratron).

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

1957 National Electronics

Published operating points and test conditions from this source.

SECTION 1

Thyratron

Other

  • Maximum DC output current

    4 A

  • Maximum instantaneous output current

    12 A

  • Maximum peak inverse voltage

    1500 V

  • Maximum peak forward voltage

    1500 V

Characteristic

  • Filament heating time

    15 s

  • Typical arc drop

    15 V

Construction

  • Filling

    Argon/mercury vapor

Application

  • Service

    Industrial grid-controlled rectifier

  • Service

    Motor speed control