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Specialized - Thyratron ·Thyratron

716

Mercury-vapor negative-control thyratron for controlled rectifier service. Its heavy cathode supports substantial grid-triggered power switching.

Directly heatedCold cathodeCommon cathodeDissimilarSpecialized
Sections
1
Base
4D
Socket code
IO
Base pins
4
Nominal heater
2.5 V / 6.3 A

Description

RCA 716/6855 is a directly heated gas-and-mercury-vapor thyratron for grid-controlled rectifier service, rated for 1250-V peak forward/inverse anode voltage and high peak cathode current.

Socket description

International Octal

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base
4D
Socket code
IO
Base pins
4
Nominal heater voltage
2.5 V
Nominal heater current
6.3 A
Parallel heater voltage
-
Parallel heater current
-
Series capable
No

4D - 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 plate voltage
1250 V
Max cathode current
8 A
Rectifier forward voltage drop
8 V

Thyratron section; peak/average current, inverse voltage, timing, and gas/mercury data retained 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

1971 RCA HB3 Binder 2 of 7

Published operating points and test conditions from this source.

SECTION 1

Thyratron

Other

  • Filament voltage

    2.5 V

    Nominal

  • Filament current

    6.3 A

    Nominal

  • Maximum deionization time

    1000 us

  • Maximum critical grid current

    10 uA

  • Peak forward anode voltage

    1250 V

  • Peak inverse anode voltage

    1250 V

  • Peak negative grid voltage before conduction

    500 V

  • Peak negative grid voltage during conduction

    10 V

  • Peak anode/cathode current

    8 A

  • Average anode/cathode current

    1 A

  • Fault current

    80 A

    Short-duration fault rating

  • Ambient or condensed-mercury operating temperature range

    -40 to +80 condensed-mercury operating range C

Characteristic

  • Minimum heating time prior to tube conduction

    15 s

  • Ionization time

    10 us

    Approximate

  • Anode voltage drop

    8 V

Capacitance

  • Grid-to-anode capacitance

    3 pF

    Approximate