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21EP4C

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: 12N
Socket code: -
Base pins: 5
Nominal heater: 6.3 V / 600 mA

Description

21EP4C is a picture tube using magnetic 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: 12N
Socket code: -
Base pins: 5
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: 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

Characteristic

Heater current
60 mA
At6.3V
Faceplate light transmission
74 %
Approximate

Capacitance

Cathode to all other electrodes
5 pF
External conductive coating to anode capacitance
- to 750 pF

Other

Maximum grid 2 voltage
550 V
Maximum grid 1 negative-bias voltage
155 V
NegativeBias
Maximum grid 1 positive-bias voltage
0 V
PositiveBias
Maximum grid 1 positive-peak voltage
2 V
PositivePeak
Maximum grid 1 negative-peak voltage
220 V
NegativePeak
Projected screen area
248 in^2
Typical anode/ultor voltage
12000 V