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21DHP4

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: 8HR
Socket code: -
Base pins: -
Nominal heater: 6.3 V / 450 mA

Description

A lightweight 21-inch direct-view rectangular glass television picture tube with electrostatic focus, 110-degree magnetic deflection, gray filter glass and an aluminized P4 screen, using a 450 mA heater.

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base: 8HR
Socket code: -
Base pins: -
Nominal heater voltage: 6.3 V
Nominal heater current: 450 mA
Parallel heater voltage: -
Parallel heater current: -
Series capable: No

8HR - 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: 19800 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 warm-up time
11 s
Faceplate light transmission
76 %
Approximate

Capacitance

Grid 1 to all other electrodes
6 pF
Cathode to all other electrodes
5 pF

Other

Maximum grid 2 voltage
550 V
Maximum grid 1 negative-bias voltage
154 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
Grid 4 focus voltage
0 to 400 V
Focus
Projected screen area
262 in^2