Skip to main content

Specialized - Cathode Ray ·CathodeRay

21KP4A

Twenty-one-inch rectangular direct-view television picture tube with electrostatic focus, magnetic deflection, gray-filter faceplate, external single-field ion trap, and white P4 medium-persistence screen for monochrome receiver service.

Directly heatedCold cathodeCommon cathodeDissimilarSpecialized
Sections
1
Base
-
Socket code
B12D
Base pins
12
Nominal heater
6.3 V / 600 mA

Description

A-version of the 21KP4 electrostatically focused, magnetically deflected television picture tube.

Socket description

Duodecar 12-contact

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base
-
Socket code
B12D
Base pins
12
Nominal heater voltage
6.3 V
Nominal heater current
600 mA
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

Cathode Ray

X-ray radiationInterelectrode capacitances
Max plate voltage
20000 V
Max screen voltage
410 V

Published promoted fields populated by printed ratings/characteristics headings.

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

1961 Tung Sol

Published operating points and test conditions from this source.

SECTION 1

Cathode Ray

Other

  • HighVoltageAnodeMaximum

    20000 V

    CRT

Capacitance

  • CathodeToOtherElectrodesCapacitance

    5 pF

    Approximate

Data set 02

1966 Tung Sol Electronic Tubes 4 of 4

Published operating points and test conditions from this source.

SECTION 1

Cathode Ray

Construction

  • Focusing method

    Electrostatic

  • Deflecting method

    Magnetic

  • Phosphor

    P4

    White;MediumPersistence

Characteristic

  • Deflection angle

    70 deg

    Approximate

  • Faceplate light transmission at center

    66 %

    Approximate

Other

  • Heater voltage

    6.3 V

  • Heater current

    600 mA

  • Maximum DC anode voltage

    15000 V

  • Maximum DC grid #2 voltage

    410 V

  • Maximum grid #1 negative-bias magnitude

    125 V

  • Maximum grid #1 positive DC voltage

    0 V

  • Maximum grid #1 positive peak voltage

    2 V

  • Typical DC anode voltage

    12000 V

    TelevisionPictureTube

  • Typical DC grid #2 voltage

    300 V

    TelevisionPictureTube

  • Typical grid #1 voltage minimum

    -77 V

    VisualExtinctionRange

  • Typical grid #1 voltage maximum

    -33 V

    VisualExtinctionRange

  • Maximum grid #1 circuit resistance

    1.5 megohm

  • Ion trap magnet rated strength

    50 gauss

    Approximate

  • Focusing electrode voltage minimum

    -500 V

    ElectrostaticFocus

  • Focusing electrode voltage maximum

    1000 V

    ElectrostaticFocus

  • Centering magnet field strength maximum

    8 gauss

    Approximate

Capacitance

  • Cathode-to-all-other-electrodes capacitance

    6 pF

    Approximate

  • Grid #1-to-all-other-electrodes capacitance

    6.5 pF

    Approximate

Application

  • Application

    Direct-view television picture tube