Skip to main content
Tube Tinker — Electron Tube Database
Alternatives & variationsDownload PDF datasheet

Specialized - Cathode Ray ·CathodeRay

21ECP7

Twenty-one-inch P7 cathode-ray display tube using magnetic focusing and magnetic deflection at comparatively low anode voltage. Its persistent-screen designation and approximately 9 kV maximum distinguish it from conventional P4 television picture tubes.

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

Description

Low-anode-voltage magnetically focused and deflected cathode-ray tube.

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
12N
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

12N - 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
9000 V
Max screen voltage
500 V

Low-anode-voltage magnetically focused and deflected cathode-ray tube.

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

1945 Continental Electronics

Published operating points and test conditions from this source.

SECTION 1

Cathode Ray

Characteristic

  • Focusing Method

    Magnetic

  • Deflecting Method

    Magnetic

  • Horizontal Deflection Angle

    65 deg

    Approximate

  • Vertical Deflection Angle

    50 deg

    Approximate

  • Phosphor

    P7

Other

  • Anode Voltage Minimum

    5000 to - V

  • Anode Voltage Typical

    5000 V

    Grid drive service

  • Grid 2 Voltage Typical

    300 V

    Grid drive service

  • Grid 1 Voltage

    -72 to -28 V

    Grid drive service