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21DLP4

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: DUODECAL5
Base pins: -
Nominal heater: 6.3 V / 600 mA

Description

The Westinghouse 21DLP4 is a 21-inch 90-degree aluminized P4 CRT with gray filter glass and no ion trap.

Socket description

Small-shell Duodecal 5-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: DUODECAL5
Base pins: -
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

1965 Westinghouse Data Book

Published operating points and test conditions from this source.

SECTION 1

Cathode Ray

Characteristics

Heater Voltage
6.3 V
Heater Current
600 mA
Heater Warm-up Time
11 s
Focusing Method
Low Voltage Electrostatic text
Deflection Method
Magnetic text
Horizontal Deflection Angle
85 deg
Approximate
Vertical Deflection Angle
68 deg
Approximate
Diagonal Deflection Angle
90 deg
Approximate
Phosphor
Aluminized P4 text
Fluorescence
White text
Persistence
Short to Medium text
Light Transmittance
73 percent
Approximate
Cathode-to-All Capacitance
5 pF
Approximate
Grid1-to-All Capacitance
6 pF
Approximate
External Coating-to-Anode Capacitance Minimum
2000 pF
External Coating-to-Anode Capacitance Maximum
2500 pF

Other

Maximum Anode Voltage
20000 V
Minimum Anode Voltage
11000 V
Maximum Focus Electrode Voltage Positive
1100 V
Grid4
Maximum Focus Electrode Voltage Negative
-550 V
Grid4
Maximum Grid2 Voltage
500 V
Minimum Grid2 Voltage
200 V
Maximum Heater-Cathode Voltage During Warmup
450 V
Duration<=15s
Maximum Heater-Cathode Voltage After Warmup
180 V
Typical Anode Voltage
16000 V
CathodeDrive
Typical Focus Voltage Minimum
0 V
Grid4
Typical Focus Voltage Maximum
400 V
Grid4
Typical Grid2 Voltage
450 V
CathodeDrive
Cathode Voltage for Raster Cutoff Minimum
45 V
CathodeDrive
Cathode Voltage for Raster Cutoff Maximum
105 V
CathodeDrive
Maximum Grid1 Circuit Resistance
1.5 Mohm

Data set 02

1971 RCA HB3 Binder 1 of 7

Published operating points and test conditions from this source.

SECTION 1

Cathode Ray

Capacitance

Grid 1 to all other electrodes
6 pF
Cathode to all other electrodes
5 pF
External conductive coating to anode capacitance
- to 2500 pF

Other

Maximum grid 2 voltage
500 V
Maximum grid 1 voltage
640 V
Maximum grid 1 negative-bias voltage
140 V
NegativeBias
Maximum grid 1 positive-bias voltage
0 V
PositiveBias
Maximum grid 1 positive-peak voltage
200 V
PositivePeak
Maximum grid 1 negative-peak voltage
200 V
NegativePeak
Peak heater-cathode voltage
180 V
HeaterNegativeOperating
Peak heater-cathode voltage
180 V
HeaterPositive
Projected screen area
262 in^2

Characteristic

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