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Specialized - Cathode Ray ·CathodeRay

21DSP4

Twenty-one-inch direct-view monochrome television picture tube with magnetic deflection and a P4 display screen. Manufacturer documentation places it in the high-voltage receiver CRT family, with construction optimized for bright rectangular picture presentation.

Directly heatedCold cathodeCommon cathodeDissimilarSpecialized
Sections
1
Base
12L
Socket code
-
Base pins
6
Nominal heater
6.3 V / 600 mA

Description

21DSP4 is a picture tube using electrostatic focusing and magnetic deflection. The source specifies a P4 screen and publishes CRT accelerating/anode ratings, control and focusing-electrode limits, heater-cathode limits, capacitances, and operating or deflection characteristics.

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base
12L
Socket code
-
Base pins
6
Nominal heater voltage
6.3 V
Nominal heater current
600 mA
Parallel heater voltage
-
Parallel heater current
-
Series capable
No

12L - 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

CRT maximum accelerating/anode/ultor voltage is promoted to MaxPlateVoltage; additional electrode ratings, capacitances, operating conditions, focus/deflection and optical data are preserved 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 1 of 7

Published operating points and test conditions from this source.

SECTION 1

Cathode Ray

Other

  • Maximum grid 2 voltage

    64 V

  • Maximum grid 1 negative-bias voltage

    0 V

    NegativeBias

  • Maximum grid 1 positive-bias voltage

    140 V

    PositiveBias

  • Maximum grid 1 positive-peak voltage

    200 V

    PositivePeak

  • Maximum grid 1 negative-peak voltage

    2 V

    NegativePeak

  • Peak heater-cathode voltage

    180 V

    HeaterNegativeOperating

  • Projected screen area

    262 in^2

Characteristic

  • Grid 4 current

    -25 to 25 µa

  • Grid 2 current

    -15 to 15 µa

  • Diagonal deflection angle

    90 deg

    Approximate

  • Horizontal deflection angle

    85 deg

    Approximate

  • Vertical deflection angle

    68 deg

    Approximate

  • Faceplate light transmission

    74 %

    Approximate