17BNP4 Cathode Ray Tube

A direct-view, rectangular glass picture tube designed for television applications, featuring electrostatic focus, magnetic deflection, and an aluminized screen.

Overview

The 17BNP4 is a cathode ray tube designed for television display systems. It utilizes electrostatic focusing and magnetic deflection, incorporating a unipotential cathode and an aluminized screen. The tube features a gray filter faceplate and does not require an external ion trap. Depending on the specific design configuration, the nominal raster size is specified as either 10 5/16" x 11 1/8" or 14 5/16" x 11 1/8".

Mechanical and Physical Specifications

The 17BNP4 is constructed with a rectangular glass envelope. Its physical dimensions and tolerances are as follows:

The electrical connection to the high-voltage anode is made via a recessed small cavity cap (J1-21) located on the bulb. This contact aligns with pin position #6 within a tolerance of ± 30 degrees. The base is a small shell duodecal 6-pin configuration (B6-63) with a 12L basing arrangement.

Electrical Connections and Basing

The 12L basing arrangement provides the following pin connections, viewed from the bottom of the tube:

• Pin 1: Heater
• Pin 2: Grid No. 1
• Pin 6: Grid No. 4
• Pin 10: Grid No. 2
• Pin 11: Cathode
• Pin 12: Heater
• Anode Cap: Grid No. 3, Grid No. 5

The heater is designed for a nominal supply voltage of 6.3 Volts and draws a nominal current of 0.6 Ampere.

Deflection, Optical, and Capacitance Characteristics

The tube is designed for magnetic deflection with wide-angle coverage:

• Horizontal Deflection Angle: 85 degrees
• Vertical Deflection Angle: 68 degrees
• Diagonal Deflection Angle: 90 degrees

Optical Performance

The screen utilizes a P-4 phosphor, which provides a white fluorescent and white phosphorescent display with short persistence. The center of the gray filter faceplate has an approximate light transmission of 74%.

Interelectrode Capacitances

The approximate capacitances of the tube electrodes are:

• Cathode to all other electrodes: 5 µµf
• Grid #1 to all other electrodes: 6 µµf
• External conductive coating to anode: 750 µµf (minimum) to 1500 µµf (maximum)

Maximum Ratings (Design Center System)

The maximum ratings for the 17BNP4 under Cathode Drive Service are defined as follows:

• Maximum DC Anode Voltage: 18,000 Volts (Anode voltage should not be operated below 12,000 Volts to maintain acceptable brilliance and definition)
• Maximum DC Grid #4 Voltage: -500 to +1000 Volts
• Maximum DC Grid #2 Voltage: 200 Volts
• Maximum Grid #1 Voltage:
  • DC negative-bias value: 125 Volts
  • DC positive-bias value: 0 Volts
  • Positive-peak value: 0 Volts
• Maximum DC Peak Heater-Cathode Voltage:
  • Heater negative with respect to cathode (during warm-up period ≤ 15 seconds): 410 Volts
  • Heater negative with respect to cathode (after warm-up): 180 Volts
  • Heater positive with respect to cathode: 180 Volts
• Maximum Grid #1 Circuit Resistance: 1.5 Megohms

Typical Operating Conditions and Drive Configurations

Under typical operating conditions in Cathode Drive Service, the tube is operated with the following parameters:

• DC Anode Voltage: 14,000 Volts
• DC Grid #4 Voltage: -50 to +350 Volts
• DC Grid #2 Voltage: 110 Volts
• DC Grid #1 Voltage (for visual extinction of focused raster): -37 to -50 Volts

Grid Drive Operation

The 17BNP4 can also be operated in Grid Drive configurations, though this mode is associated with some loss in efficiency. The average raster cutoff voltage ($E_{g1co}$) under grid drive can be calculated using the following formulas:

• $E_{g1co} = -(0.502 \times E_{[g2](/tubes/G2)} + 5.8)$
• $E_{g1co} = -0.502 \times E_{[g2](/tubes/G2)} + 5.8$

In these calculations, $E_{[g2](/tubes/G2)}$ represents the DC Grid No. 2 voltage.

Technical Summary

The 17BNP4 is a rectangular, direct-view cathode ray tube designed for television receivers. It features electrostatic focus, magnetic deflection (90-degree diagonal), and a P-4 phosphor screen. Operating with a 6.3 V, 0.6 A heater, the tube is primarily rated for Cathode Drive Service with a typical anode voltage of 14,000 Volts, but it can also be operated in Grid Drive configurations. Its physical design includes a small shell duodecal 6-pin base and a recessed small cavity cap for anode connections, providing a robust and standardized interface for television receivers.