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Specialized - Cathode Ray ·CathodeRay

20TP4

Twenty-inch direct-view monochrome television picture tube with magnetic deflection and a white P4 screen. Manufacturer data specifies high-voltage CRT operation and focusing characteristics for large-screen receiver display service.

Directly heatedCold cathodeCommon cathodeDissimilarSpecialized
Sections
1
Base
-
Socket code
-
Base pins
7
Nominal heater
6.3 V / 450 mA

Description

20TP4 is a monochrome cathode-ray picture tube for television/display service. The supplied RCA data describes electrostatic focusing and magnetic deflection, with a P4 phosphor screen.

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base
-
Socket code
-
Base pins
7
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
Max plate voltage
23000 V

Cathode-ray electron-gun/screen system; anode/ultor maximum promoted to MaxPlateVoltage when explicitly published. Explicit X-ray warning/precaution or X-radiation characteristic is present in the supplied source.

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 1 of 7

Published operating points and test conditions from this source.

SECTION 1

Cathode Ray

Other

  • Heater Voltage

    6.3 V

    Nominal heater voltage

  • Heater Current

    450 mA

    Nominal heater current

  • Phosphor

    P4

    Published phosphor designation

  • External conductive coating ~

    2000 pF

    External conductive coating ~ 2000 max. pF

  • Projected Area of Screen

    184 sq in

    Projected Area of Screen 184 sq. in

  • Grid-No.2 Voltage ~

    550 V

    Grid-No.2 Voltage ~ 550 max. V

  • Heater Voltage f

    6.9 V

    Heater Voltage f 6.9 max. V

  • Peak Heater-Cathode Voltage

    15.7 V

    Peak Heater-Cathode Voltage: 15.7 min. V

  • Combined AC & DC Voltage

    200 V

    Combined AC & DC Voltage 200 max. V

  • Anode Voltage

    0 V

    Anode Voltage 16,000 V

  • Grid-No.4 Voltageb

    200 V

    Grid-No.4 Voltageb 200 V

  • Grid-No.2 Voltage

    300 V

    Grid-No.2 Voltage 300 V

  • raster

    28 to 62 V

    raster 28 to 62 V

  • +400 volts with the combined grid-No.l voltage and video

    400 V

    +400 volts with the combined grid-No.l voltage and video-

Construction

  • Focusing Method

    Electrostatic

    Published focusing method

  • Deflection Method

    Magnetic

    Published deflection method

Characteristic

  • 114° Magnetic Deflection

    114 deg

    114° Magnetic Deflection

Capacitance

  • Cathode to all other electrodes

    5 pF

    Cathode to all other electrodes 5 pF

  • Grid No.l to all other electrodes

    6 pF

    Grid No.l to all other electrodes 6 pF

  • to anode° l

    1400 pF

    to anode° l 1400 min. pF

  • Heater Current at

    20 mA

    Heater Current at 6.3 volts 450 ± 20 mA

  • Heater Warm-Up Time (Average)

    11 s

    Heater Warm-Up Time (Average) 11 seconds