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Specialized - Cathode Ray ·CathodeRay

19AP4

P4 high-voltage cathode-ray picture-display tube with magnetic focusing and deflection; this 19AP4 variant differs principally in faceplate treatment, with manufacturer documentation warning about X-ray shielding above 16 kV.

Directly heatedCold cathodeCommon cathodeDissimilarSpecialized
Sections
1
Base
12D
Socket code
DUODECAL5
Base pins
5
Nominal heater
6.3 V / 600 mA

Description

19AP4 — Direct-View Metal-Cone Picture Tube

The 19AP4 is a direct-view cathode ray picture tube designed primarily for television receiver applications. It features a round metal-cone construction, a unipotential cathode, and utilizes magnetic focus and magnetic deflection. The tube is designed to operate with an external, single-field ion trap magnet to prevent ion-burn damage to the screen.

Construction and Mechanical Specifications

The 19AP4 is distinguished by its round metal-cone envelope and a clear glass faceplate. This clear faceplate differentiates the base 19AP4 from its later variants in the same family.

The physical dimensions and mechanical characteristics of the tube include:

  • Overall Length: 21 1/2 ± 1/2 inches
  • Greatest Diameter of Bulb: 18 5/8 ± 1/8 inches
  • Minimum Useful Screen Diameter: 17 3/8 inches
  • Bulb Contact: Metal shell lip
  • Base: Small shell duodecal 5-pin (B5-57)
  • Basing Configuration: 12D

The raster size produced on the screen is approximately 11 3/8 to 11 3/4 inches by 15 3/8 to 15 3/4 inches.

Optical Characteristics

The screen of the 19AP4 utilizes Phosphor No. 4, which provides a white fluorescent color and a white phosphorescent color with medium persistence. The clear glass faceplate has a light transmission of approximately 66% at the center of the screen.

Electrical Connections and Interelectrode Capacitances

The 19AP4 uses a duodecal 5-pin base (B5-57) with a 12D basing arrangement. The electrical connections, viewed from the bottom of the base, are assigned as follows:

Pin / ContactElectrode Connection
Pin 1Heater
Pin 2Grid No. 1
Pin 10Grid No. 2
Pin 11Cathode
Pin 12Heater
Metal Shell LipGrid No. 3, Anode

The tube has an approximate deflection angle of 66 degrees. The direct interelectrode capacitances are:

  • Cathode to all other electrodes: Approximately 5 μμF
  • Grid No. 1 to all other electrodes: Approximately 7 μμF

Maximum Ratings (Design Center Values)

The operating limits for the 19AP4 are established under the design center rating system. Operating the tube beyond these limits may impair performance or cause permanent damage.

  • Heater Voltage: 6.3 Volts
  • Heater Current: 0.6 Amp
  • Maximum DC Anode Voltage: 19,000 Volts (Note: If operated in excess of 16,000 Volts, X-ray radiation shielding may be necessary to avert personal injury)
  • Maximum DC Grid No. 2 Voltage: 410 Volts
  • Maximum Grid No. 1 Voltage:
    • DC Negative-Bias Value: 125 Volts
    • DC Positive-Bias Value: 0 Volts
    • Positive-Peak Value: 2 Volts
  • Maximum DC Peak Heater-Cathode Voltage:
    • Heater negative with respect to cathode during warm-up (≤ 15 seconds): 410 Volts
    • Heater negative with respect to cathode after warm-up: 150 Volts
    • Heater positive with respect to cathode: 150 Volts
  • Maximum Grid No. 1 Circuit Resistance: 1.5 Megohms

Typical Operating Conditions and Characteristics

Under typical operating conditions, the 19AP4 is set up with the following parameters:

  • DC Anode Voltage: 12,000 Volts
  • DC Grid No. 2 Voltage: 300 Volts
  • DC Grid No. 1 Voltage (for visual extinction of the undeflected focused spot): -33 to -77 Volts
  • DC Focusing Coil Current: 140 ± 20% mA
    • Focusing Conditions: This current is specified using a standard focus coil #106 or equivalent, with the center of the focus coil air gap positioned 3.0 inches from the reference line. The combined Grid No. 1 bias and video signal are adjusted to produce a highlight brightness of 18 foot-lamberts on the picture screen.
  • DC Ion Trap Current: 75 ± 50% mA (using standard single-field ion trap coil #111)

Associated Family Variants

The 19AP4 is the parent type of a family of tubes sharing similar physical dimensions and electrical characteristics, but differing in faceplate treatment and screen technology:

  • 19AP4: Clear glass faceplate.
  • 19AP4A: Grey filter faceplate to improve contrast.
  • 19AP4B: Frosted filter faceplate to reduce glare.
  • 19AP4C: Grey filter faceplate combined with an aluminized screen for increased brightness.
  • 19AP4D: Clear frosted faceplate.

Technical Summary

The 19AP4 is a 19-inch class, round metal-cone cathode ray tube designed for television display applications. It features a 66-degree deflection angle, magnetic focus, and magnetic deflection, requiring an external single-field ion trap magnet. Operating with a standard 6.3 V, 0.6 A heater, the tube is rated for a maximum anode voltage of 19,000 V, with typical operation at 12,000 V. The 19AP4 is characterized by its clear glass faceplate, distinguishing it from other members of the 19AP4 family (such as the 19AP4A, B, C, and D variants) which incorporate grey filters, frosting, or aluminized screens.

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
12D
Socket code
DUODECAL5
Base pins
5
Nominal heater voltage
6.3 V
Nominal heater current
600 mA
Parallel heater voltage
-
Parallel heater current
-
Series capable
No

12D - 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
19000 V
Max screen voltage
410 V

CRT-specific electrode, focusing and deflection data retained 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

1961 Tung Sol

Published operating points and test conditions from this source.

SECTION 1

Cathode Ray

Other

  • Maximum Anode Voltage

    19000 V

  • Typical Anode Voltage

    12000 V

  • Maximum Grid2 Voltage

    410 V

  • Typical Grid2 Voltage

    300 V

Characteristic

  • DeflectionAngleApproximate

    66 degree

  • FocusingMethod

    Magnetic

  • DeflectingMethod

    Magnetic

  • PhosphorNumber

    4

  • FluorescentColor

    White

  • Persistence

    Medium

  • FaceplateVariant

    Clear glass faceplate

Data set 02

1966 Tung Sol Electronic Tubes 4 of 4

Published operating points and test conditions from this source.

SECTION 1

Cathode Ray

Characteristics

  • DEFLECTION ANGLE (APPROX.)

    66 degrees

    Published CRT datasheet value; multiple values on a row correspond to separate source-table conditions or limits.

  • FACEPLATE LIGHT TRANSMISSION

    66 percent

    Published CRT datasheet value; multiple values on a row correspond to separate source-table conditions or limits.

  • HEATER

    6.3 V

    Published CRT datasheet value; multiple values on a row correspond to separate source-table conditions or limits.

  • A IF THIS TUBE IS OPERATED AT VOLTAGES IX E%LESS OF 16,000 VOLTS %—RAY RADIATION SHIELD LNG MAY — value 1

    16 V

    Published CRT datasheet value; multiple values on a row correspond to separate source-table conditions or limits.

  • A IF THIS TUBE IS OPERATED AT VOLTAGES IX E%LESS OF 16,000 VOLTS %—RAY RADIATION SHIELD LNG MAY — value 2

    0 V

    Published CRT datasheet value; multiple values on a row correspond to separate source-table conditions or limits.

  • DC ANODE

    12 V

    Published CRT datasheet value; multiple values on a row correspond to separate source-table conditions or limits.

  • DC GRID #2 VOLTAGE — value 1

    2 V

    Published CRT datasheet value; multiple values on a row correspond to separate source-table conditions or limits.

  • DC GRID #2 VOLTAGE — value 2

    300 V

    Published CRT datasheet value; multiple values on a row correspond to separate source-table conditions or limits.

  • DC FOCUSING COIL CURRENTC (APPROX.) — value 1

    140 mA

    Published CRT datasheet value; multiple values on a row correspond to separate source-table conditions or limits.

  • DC FOCUSING COIL CURRENTC (APPROX.) — value 2

    20 mA

    Published CRT datasheet value; multiple values on a row correspond to separate source-table conditions or limits.

  • G FOR STANDARD FOCUS COIL 4106, OR EQUIVALENT S WITH THE COMBINED GRID N1 BIAS VOLTAGE AMD

    4106 V

    Published CRT datasheet value; multiple values on a row correspond to separate source-table conditions or limits.

  • VIDEO SIGNAL VOLTAGE ADJUSTED TO PRODUCE A XiGnL IGnT BRIGHTNESS OF 18 F00T LANBERTS ON A

    18 V

    Published CRT datasheet value; multiple values on a row correspond to separate source-table conditions or limits.

  • 11 j/4" % 15 j/R" PICTURE SIZE. DISTANCE FROM REFERENCE LINE TO CENTER OF 41R GAP ON FOCUS — value 1

    4

    Published CRT datasheet value; multiple values on a row correspond to separate source-table conditions or limits.

  • 11 j/4" % 15 j/R" PICTURE SIZE. DISTANCE FROM REFERENCE LINE TO CENTER OF 41R GAP ON FOCUS — value 2

    15

    Published CRT datasheet value; multiple values on a row correspond to separate source-table conditions or limits.

  • 11 j/4" % 15 j/R" PICTURE SIZE. DISTANCE FROM REFERENCE LINE TO CENTER OF 41R GAP ON FOCUS — value 3

    41

    Published CRT datasheet value; multiple values on a row correspond to separate source-table conditions or limits.

Other

  • MAXIMUM DC ANODE

    19000 V

    Published CRT datasheet value; multiple values on a row correspond to separate source-table conditions or limits.

  • MAXIMUM DC GRID #2 VOLTAGE — value 1

    2 V

    Published CRT datasheet value; multiple values on a row correspond to separate source-table conditions or limits.

  • MAXIMUM DC GRID #2 VOLTAGE — value 2

    410 V

    Published CRT datasheet value; multiple values on a row correspond to separate source-table conditions or limits.

  • MAXIMUM GRID #1 VOLTAGE

    1 V

    Published CRT datasheet value; multiple values on a row correspond to separate source-table conditions or limits.

  • MAXIMUM GRID #1 CIRCUIT RESISTANCE — value 1

    1 mA

    Published CRT datasheet value; multiple values on a row correspond to separate source-table conditions or limits.

  • MAXIMUM GRID #1 CIRCUIT RESISTANCE — value 2

    1.5 mA

    Published CRT datasheet value; multiple values on a row correspond to separate source-table conditions or limits.