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Specialized - Cathode Ray ·CathodeRay

12BNP4A

Cathode-ray display tube documented by manufacturer data for type 12BNP4A; available extracted source information is sparse, so no more specialized application or construction claim is made.

Directly heatedCold cathodeCommon cathodeDissimilarSpecialized
Sections
1
Base
-
Socket code
-
Base pins
-
Nominal heater
6.9 V / 20 A

Description

12BNP4A Picture Tube

The 12BNP4A is a PAN-O-PLY type cathode-ray tube designed for television receiver applications. It features a low-voltage electrostatic focus system and a 110-degree magnetic deflection angle. The tube utilizes an electron gun design that does not require an ion-trap magnet.

Mechanical Design and Physical Dimensions

The 12BNP4A is constructed using a J99C/E glass bulb envelope. It has a nominal weight of approximately 5 pounds. The physical dimensions of the tube are characterized by the following specifications:

  • Overall Length: 9.348 ± 0.250 inches
  • Neck Length: 4.375 ± 0.125 inches
  • Neck Diameter: 1.125 (+0.043 / -0.025) inches
  • Projected Area of Screen: 74 square inches
  • Minimum Screen Dimensions: Diagonal of 11.625 inches, height of 7.625 inches, and width of 10.125 inches.
  • Outer Envelope Dimensions: Diagonal of 12.429 ± 0.125 inches, height of 8.619 ± 0.125 inches, and width of 10.991 ± 0.125 inches.

The faceplate is made of filterglass with a light transmission at the center of approximately 49%. The screen utilizes an aluminized P4-sulfide type phosphor.

For electrical shielding and mechanical integration, the tube features a Regular-Band type external conductive coating, which includes implosion protection hardware. The contact area for grounding this coating is located near the reference line, which is determined by a JEDEC No. G-126 gauge.

Electrical Connections and Basing

The 12BNP4A utilizes a Small-Button Neoeightar 7-Pin base (Arrangement 1, JEDEC No. B7-208) and a Recessed Small Cavity anode cap (JEDEC No. J1-21). The basing designation is 8HR, viewed from the bottom of the tube. The pin and cap connections are assigned as follows:

Pin / CapConnection
Pin 1Heater
Pin 2Grid No. 1
Pin 3Grid No. 2
Pin 4Grid No. 4
Pin 6Grid No. 1
Pin 7Cathode
Pin 8Heater
CapAnode (Grid No. 3, Grid No. 5, Screen, Collector)
CExternal Conductive Coating

The direct interelectrode capacitances of the tube are:

  • Cathode to all other electrodes: 5 pF
  • Grid No. 1 to all other electrodes: 6 pF
  • External conductive coating to anode: 550 pF minimum to 850 pF maximum (including the implosion protection hardware).

Heater Specifications and Design-Maximum Ratings

The heater is designed to operate within a voltage range of 5.7 V minimum to 6.9 V maximum, with a nominal current of 450 ± 20 mA at 6.3 V. The average heater warm-up time is 11 seconds.

The design-maximum ratings for the 12BNP4A, with voltages stated as positive with respect to the cathode, are defined as follows:

  • Anode Voltage: 9,000 V minimum to 15,000 V maximum
  • Grid-No. 4 Voltage: Positive value of 1,100 V maximum; negative value of 550 V maximum
  • Grid-No. 2 Voltage: 125 V minimum to 550 V maximum
  • Grid-No. 1 Voltage:
    • Negative peak value: 220 V maximum
    • Negative bias value: 155 V maximum
    • Positive bias value: 0 V maximum
    • Positive peak value: 2 V maximum
  • Peak Heater-Cathode Voltage:
    • Heater negative with respect to cathode: 450 V maximum during the equipment warm-up period (less than or equal to 15 seconds); 300 V maximum after the equipment warm-up period.
    • Heater positive with respect to cathode: 200 V maximum combined AC & DC voltage; 100 V maximum DC component.

Typical Operating Conditions for Cathode-Drive Service

Under typical cathode-drive operating conditions, where voltages are positive with respect to Grid No. 1, the operating parameters are:

  • Anode Voltage: 13,000 V
  • Grid-No. 4 Voltage: 100 V (The actual voltage required for optimum focus on any individual tube can range from -100 V to +300 V when the combined cathode and video-signal voltage is adjusted to produce an anode current of 75 microamperes on a 6-3/4-inch by 9-inch pattern).
  • Grid-No. 2 Voltage: 140 V
  • Cathode Voltage: 22 V to 42 V (for visual extinction of a focused raster)
  • Centering Magnet Field Strength: 0 to 12 Gauss (using a required adjustable centering magnet)
  • Maximum Grid-No. 1 Circuit Resistance: 1.5 MΩ

Technical Summary

The 12BNP4A is an electrostatic-focus, magnetic-deflection picture tube featuring a 110-degree deflection angle, a P4-sulfide aluminized phosphor screen, and a 49% light-transmission filterglass faceplate. Operating with a 6.3 V heater and requiring no ion-trap magnet, it is designed for cathode-drive service with an anode voltage rating up to 15,000 V. Its mechanical integration is supported by a Neoeightar 7-pin base, a recessed small cavity anode cap, and a regular-band external conductive coating that incorporates implosion protection hardware.

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base
-
Socket code
-
Base pins
-
Nominal heater voltage
6.9 V
Nominal heater current
20 A
Parallel heater voltage
-
Parallel heater current
-
Series capable
No

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 screen voltage
550 V

CRT-specific ratings, operating conditions, capacitances, focus/deflection, cutoff, optical, and screen data are retained in section 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

Characteristics

  • NO ION-TRAP MAGNET FEQUIRED — published value 1

    1 mA

    Published CRT datasheet value; multiple numbers on one source row represent its separate limits or operating conditions.

  • NO ION-TRAP MAGNET FEQUIRED — published value 2

    10 mA

    Published CRT datasheet value; multiple numbers on one source row represent its separate limits or operating conditions.

  • Grid No.1 to al l . other electrodes

    6 pF

    Published CRT datasheet value; multiple numbers on one source row represent its separate limits or operating conditions.

  • External conductive — published value 1

    550 mA

    Published CRT datasheet value; multiple numbers on one source row represent its separate limits or operating conditions.

  • External conductive — published value 2

    850 mA

    Published CRT datasheet value; multiple numbers on one source row represent its separate limits or operating conditions.

  • Heater Current at 6.3 V — published value 1

    6.3 mA

    Published CRT datasheet value; multiple numbers on one source row represent its separate limits or operating conditions.

  • Heater Current at 6.3 V — published value 2

    450 mA

    Published CRT datasheet value; multiple numbers on one source row represent its separate limits or operating conditions.

  • Heater Current at 6.3 V — published value 3

    20 mA

    Published CRT datasheet value; multiple numbers on one source row represent its separate limits or operating conditions.

  • Light transmission at center (Approx )

    49

    Published CRT datasheet value; multiple numbers on one source row represent its separate limits or operating conditions.

  • Projected Area of Screen

    74

    Published CRT datasheet value; multiple numbers on one source row represent its separate limits or operating conditions.

  • Anode Voltage — published value 1

    9000 V

    Published CRT datasheet value; multiple numbers on one source row represent its separate limits or operating conditions.

  • Anode Voltage — published value 2

    -15000 V

    Published CRT datasheet value; multiple numbers on one source row represent its separate limits or operating conditions.

  • Grid-No.2 — published value 1

    125 V

    Published CRT datasheet value; multiple numbers on one source row represent its separate limits or operating conditions.

  • Grid-No.2 — published value 2

    550 V

    Published CRT datasheet value; multiple numbers on one source row represent its separate limits or operating conditions.

  • Heater Voltage — published value 1

    5 V

    Published CRT datasheet value; multiple numbers on one source row represent its separate limits or operating conditions.

  • Heater Voltage — published value 2

    7 V

    Published CRT datasheet value; multiple numbers on one source row represent its separate limits or operating conditions.

  • Heater Voltage — published value 3

    6.9 V

    Published CRT datasheet value; multiple numbers on one source row represent its separate limits or operating conditions.

  • Combined AC & DC voltage

    200 V

    Published CRT datasheet value; multiple numbers on one source row represent its separate limits or operating conditions.

  • Anode Voltage

    13000 V

    Published CRT datasheet value; multiple numbers on one source row represent its separate limits or operating conditions.

  • Grid-No.4 Voltageb

    100 V

    Published CRT datasheet value; multiple numbers on one source row represent its separate limits or operating conditions.

  • Grid-No.2 Voltage

    140 V

    Published CRT datasheet value; multiple numbers on one source row represent its separate limits or operating conditions.

  • Grid-No. l Circuit Resistance

    1.5 mA

    Published CRT datasheet value; multiple numbers on one source row represent its separate limits or operating conditions.

  • SCREEN WIDTH_,

    1.625

    Published CRT datasheet value; multiple numbers on one source row represent its separate limits or operating conditions.