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Specialized - Cathode Ray ·CathodeRay

7NP4

Seven-inch projection kinescope with electrostatic focusing, magnetic deflection, P4 screen, and forced-air cooling. RCA specifies extremely high accelerating voltage and includes explicit X-ray radiation precautions for projection operation.

Directly heatedCold cathodeCommon cathodeDissimilarSpecialized
Sections
1
Base
-
Socket code
DUODECAL11
Base pins
14
Nominal heater
6.3 V / 620 mA

Description

7NP4 is a projection kinescope using electrostatic focusing and magnetic deflection. The source specifies a P4 screen and publishes CRT accelerating-electrode ratings, control/focus electrode limits, heater-cathode limits, capacitances, and operating or deflection characteristics. Forced-air cooling is specified. The source includes an X-ray or X-radiation warning/precaution.

Socket description

Duodecal 11-contact CRT base

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base
-
Socket code
DUODECAL11
Base pins
14
Nominal heater voltage
6.3 V
Nominal heater current
620 mA
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 plate voltage
80000 V

CRT maximum accelerating/anode/ultor voltage is promoted to MaxPlateVoltage; additional electrode ratings, capacitances, operating conditions, deflection/focus 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

Other

  • Maximum grid 3 to cathode voltage

    20000 V

    GridDriveService

  • Maximum grid 2 to cathode voltage

    1050 V

    GridDriveService

  • Maximum grid 1 negative-bias voltage

    250 V

    NegativeBias

  • Maximum grid 1 positive-bias voltage

    0 V

    PositiveBias

  • Maximum grid 1 positive-peak voltage

    2 V

    PositivePeak

  • Maximum average anode current

    2 mA

  • Peak heater-cathode voltage

    410 V

    HeaterNegativeWarmup

  • Peak heater-cathode voltage

    150 V

    HeaterNegativeAfterWarmup

  • Peak heater-cathode voltage

    150 V

    HeaterPositive

  • Maximum accelerating/anode voltage

    80000 V

  • Anode-to-Grid-No. l Voltage b

    80000 V

  • Grid-No.3-to-Grid-No. l Voltage

    20000 V

  • Grid-No.2-to-Grid-No. l Voltage

    1300 V

  • Average Anode Currentb

    2 mA

  • For anode-to-grid-No.1 voltage of

    75000 V

  • Voltage for Focus

    15000 to 17000 V

  • Grid No. l Circuit Resistance

    1.5 MΩ

  • Anode-to-Cathode Voltageb

    80000 V

  • Grid-No.3-to-Cathode Voltage

    20000 V

Capacitance

  • Grid 1 to all other electrodes capacitance

    12 pF

    Approximate

  • Cathode to all other electrodes capacitance

    6 pF

    Approximate

Characteristic

  • Deflection angle

    35 degrees

    Approximate

  • Current

    620 mA

  • Deflection Angle (Approx.)

    35 degrees

  • Grid No.1 to all other electrodes

    12 pF

  • Cathode to al l other electrodes

    6 pF

  • Grid-No.2 Current

    -15 to 15 uA

  • Deflection angle

    35 degrees

    Approximate