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Tube Tinker — Electron Tube Database
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Specialized - Cathode Ray ·CathodeRay

21DRP4

Twenty-one-inch direct-view television picture tube with electrostatic focusing and magnetic deflection. National Video documents high-voltage operation around 20 kV and explicitly warns about X-ray radiation from the operating CRT.

Directly heatedCold cathodeCommon cathodeDissimilarSpecialized
Sections
1
Base
12L
Socket code
DUODECAL6
Base pins
12
Nominal heater
6.3 V / 600 mA

Description

21-inch electrostatic-focus, magnetic-deflection direct-view picture tube; X-ray warning published.

Socket description

Small-shell Duodecal 6-contact CRT base

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base
12L
Socket code
DUODECAL6
Base pins
12
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
Max screen voltage
500 V
Rectifier max heater-cathode voltage
180 V

CRT anode and grid-2 maximum ratings are promoted from the printed ratings block; other CRT-specific focus/drive/deflection values are preserved in 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

1956 National Video

Published operating points and test conditions from this source.

SECTION 1

Cathode Ray

Other

  • Typical Anode Voltage

    16000 V

  • Phosphor

    P4

Characteristic

  • Heater Voltage Nominal

    6.3 V

  • Heater Current Nominal

    600 mA

Capacitance

  • Cathode to All Other Electrodes Capacitance

    5 pF

    Approximate

  • Grid 1 to All Other Electrodes Capacitance

    6 pF

    Approximate