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Specialized - Cathode Ray ·CathodeRay

21GAP4

Twenty-one-inch 114-degree monochrome television CRT with low-voltage electrostatic focus, magnetic deflection, tension-band implosion protection, low-grid-2 cathode drive, and an aluminized P4 white screen for bright direct-view receiver service.

Directly heatedCold cathodeCommon cathodeDissimilarSpecialized
Sections
1
Base
-
Socket code
DUODECAL5
Base pins
-
Nominal heater
6.3 V / 450 mA

Description

The Westinghouse 21GAP4 is a 21-inch 114-degree banded aluminized P4 CRT with tension-band implosion protection and low-grid-2 cathode drive.

Socket description

Small-shell Duodecal 5-contact CRT base

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base
-
Socket code
DUODECAL5
Base pins
-
Nominal heater voltage
6.3 V
Nominal heater current
450 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

No fixed ratings are recorded for this section.

Television CRT electron-gun/display section.

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

1965 Westinghouse Data Book

Published operating points and test conditions from this source.

SECTION 1

Cathode Ray

Characteristics

  • Heater Voltage

    6.3 V

  • Heater Current

    450 mA

  • Heater Warm-up Time

    11 s

  • Focusing Method

    Low Voltage Electrostatic text

  • Deflection Method

    Magnetic text

  • Horizontal Deflection Angle

    102 deg

    Approximate

  • Vertical Deflection Angle

    85 deg

    Approximate

  • Diagonal Deflection Angle

    114 deg

    Approximate

  • Phosphor

    Aluminized P4 text

  • Fluorescence

    White text

  • Persistence

    Short to Medium text

  • Light Transmittance

    46 percent

    Approximate

  • Cathode-to-All Capacitance

    5 pF

    Approximate

  • Grid1-to-All Capacitance

    6 pF

    Approximate

  • External Coating-to-Anode Capacitance Minimum

    1300 pF

  • External Coating-to-Anode Capacitance Maximum

    2000 pF

Other

  • Maximum Anode Voltage

    23500 V

  • Minimum Anode Voltage

    12000 V

  • Maximum Focus Electrode Voltage Positive

    1100 V

    Grid4

  • Maximum Focus Electrode Voltage Negative

    -550 V

    Grid4

  • Maximum Grid2 Voltage

    60 V

  • Minimum Grid2 Voltage

    20 V

  • Maximum Heater-Cathode Voltage During Warmup

    450 V

    Duration<=15s

  • Maximum Heater-Cathode Voltage After Warmup

    300 V

  • Typical Anode Voltage

    16000 V

    CathodeDrive

  • Typical Focus Voltage Minimum

    0 V

    Grid4

  • Typical Focus Voltage Maximum

    400 V

    Grid4

  • Typical Grid2 Voltage

    30 V

    CathodeDrive

  • Cathode Voltage for Raster Cutoff Minimum

    30 V

    CathodeDrive

  • Cathode Voltage for Raster Cutoff Maximum

    45 V

    CathodeDrive

  • Maximum Grid1 Circuit Resistance

    1.5 Mohm