16RP4B — Picture Tube

The 16RP4B is a specialized cathode-ray picture tube designed for television display applications. It features a 70-degree magnetic deflection angle and utilizes magnetic focusing. The tube incorporates an electron gun design that does not require an external ion-trap magnet. It is equipped with an aluminized P4 sulfide-type phosphor screen and a filterglass faceplate to optimize visual performance.

Design and Mechanical Construction

The mechanical design of the 16RP4B is optimized for integration into television receivers. The tube has a total weight of approximately 16 lbs. Its physical dimensions include an overall length of 18.750 ± 0.375 inches and a neck length of 7.500 ± 0.188 inches.

Screen and Faceplate

The display area features a projected screen area of 139 square inches. The screen utilizes an aluminized P4 sulfide-type phosphor, which provides high brightness and contrast. The faceplate is constructed of filterglass with an approximate light transmission of 66%, which helps reduce reflections and improve the contrast ratio under ambient lighting conditions.

External Coating and Grounding

The tube is manufactured with a regular-band external conductive coating. This coating forms a capacitor with the internal anode conductive coating, which assists in high-voltage filtering. The contact area for grounding this external coating is located near the reference line of the bulb.

Physical Connections

The electrical interface consists of:

• Anode Connection: A recessed small cavity cap (JEDEC No. J1-21) located on the bulb cone.
• Base: A small-shell duodecal 5-pin base (JEDEC Group 4, No. B5-57).

Electrical Characteristics and Basing

The 16RP4B operates with an indirectly heated cathode. The nominal heater requirements are a voltage of 6.3 V and a current of 600 ± 30 mA.

Basing Configuration

The basing designation for the bottom view is 12N. The pin and cap assignments are structured as follows:

Direct Interelectrode Capacitances

The electrostatic capacitances between the internal electrodes are specified as:

• Cathode to all other electrodes: 5 pF
• Grid No. 1 to all other electrodes: 6 pF
• External conductive coating to anode: 750 pF minimum to 2000 pF maximum

Maximum and Minimum Ratings

The ratings for the 16RP4B are established under the Design-Maximum system. Unless otherwise specified, all voltage values are positive with respect to the cathode.

Electrode Voltages

• Anode Voltage: 17,500 max V
• Grid-No. 2 Voltage: 450 max V
• Grid-No. 1 Voltage:
  • Negative bias value: 140 max V
  • Positive bias value: 0 max V
  • Positive peak value: 2 max V

Heater and Heater-Cathode Ratings

• Heater Voltage Range: 5.7 min V to 6.9 max V
• Peak Heater-Cathode Voltage (Heater negative with respect to cathode):
  • During equipment warm-up period (not exceeding 15 seconds): 450 max V
  • After equipment warm-up period: 165 max V
• Peak Heater-Cathode Voltage (Heater positive with respect to cathode):
  • Combined AC and DC voltage: 165 max V
  • DC component: 100 max V

Circuit Constraints

• Grid-No. 1-Circuit Resistance: 1.5 max MΩ

Typical Operating Conditions (Grid-Drive Service)

In typical grid-drive service, the tube is operated under the following conditions (with voltages referenced positive to the cathode):

• Anode Voltage: 12,000 V
• Grid-No. 2 Voltage: 300 V
• Grid-No. 1 Voltage: -28 to -72 V

The Grid-No. 1 voltage range of -28 to -72 V represents the cutoff limits required for the visual extinction of the focused raster.

Technical Summary

The 16RP4B is a 70-degree magnetic deflection, magnetically focused picture tube featuring a 139 square inch screen with an aluminized P4 sulfide-type phosphor. It utilizes a 12N bottom-view basing configuration on a small-shell duodecal 5-pin base and a recessed small cavity cap for the high-voltage anode connection. Operating at a nominal heater voltage of 6.3 V, the tube is rated for a maximum anode voltage of 17,500 V and typical grid-drive operation at 12,000 V. Its design eliminates the need for an external ion-trap magnet, simplifying receiver design while maintaining reliable focus and raster extinction characteristics.