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

Voltage Regulator ·VoltageRegulator

OA3A

Improved 75 V gas voltage regulator for approximately 5–40 mA operation in stable reference and regulated-supply applications.

Directly heatedCold cathodeCommon cathodeDissimilar
Sections
1
Base
4AJ
Socket code
IO
Base pins
8
Nominal heater
-

Description

RCA OA3A is a cold-cathode glow-discharge voltage-regulator tube for maintaining a relatively constant DC output voltage despite load and supply variations. Its nominal regulated region is centered near 75 V.

Socket description

International Octal

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base
4AJ
Socket code
IO
Base pins
8
Nominal heater voltage
-
Nominal heater current
-
Parallel heater voltage
-
Parallel heater current
-
Series capable
No

4AJ - Terminal pinout

Electrical assignments shared by every tube using this base designation.

TerminalSectionConnectionEvidence
PIN2KAK — CathodeUnverified

EIA Base Connections, printed page 127, 4AJ

PIN5PAP — Plate (Anode)Unverified

EIA Base Connections, printed page 127, 4AJ

Section ratings

1 physical section, each with unique specifications.

Section 1

Voltage Regulator

X-ray radiationInterelectrode capacitances
Regulator voltage
75 V
Regulator minimum current
5 mA
Regulator maximum current
40 mA
Regulator starting voltage
160 V
Regulator maintaining voltage
75 V

Published ratings and characteristics promoted from approved datasheet.

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

Voltage Regulator

Other

  • Average starting current

    100 mA

  • DC cathode current

    5 mA to 40 mA

  • Ambient temperature range

    -55 to +90 C

  • Maximum shunt capacitance

    0.1 uF

  • Anode breakdown voltage in total darkness

    160 V

Characteristic

  • Anode breakdown / starting voltage

    160 V

  • Anode voltage drop

    70 to 81 V

  • Regulation over specified cathode-current range

    - to 6.5 V

  • Normal-light anode starting voltage

    - to 105 V

  • Anode voltage drop at 30 mA

    70 to 79 V

  • Anode voltage drop at 40 mA

    70 to 81 V

  • Maximum tube noise at 40 mA

    5 mV RMS

  • Maximum leakage current at 50-V supply

    10 uA