16ZP4 — Direct-View Cathode-Ray Picture Tube

The 16ZP4 is a direct-view cathode-ray picture tube designed specifically for television receiver applications. It features a round glass construction, a grey filter faceplate, and an external conductive coating. The tube utilizes magnetic focus and deflection, a unipotential cathode, and requires an external double field ion trap for proper operation.

Mechanical and Optical Specifications

The 16ZP4 is constructed with a round glass bulb and a grey filter faceplate that provides a light transmission of approximately 65% at the center. This faceplate design enhances picture contrast under ambient room lighting.

Physical Dimensions

• Overall Length: 22-1/4" ± 3/8"
• Greatest Diameter: 15-7/8" ± 1/8"
• Minimum Useful Screen Diameter: 14-1/2"
• Raster Size: Approximately 10-1/8" x 14-1/2" to 10-1/4" x 14-1/2"

Optical Characteristics

• Phosphor: No. 4
• Fluorescent Color: White
• Phosphorescent Color: White
• Persistence: Medium

Bulb and Base Connections

The tube is equipped with a recessed small cavity cap (J1-21) for the high-voltage anode connection. The base is a small shell duodecal 5-pin base (B5-57) with a 12N basing configuration. The recessed small cavity cap is aligned with pin position number 3 within a tolerance of ± 10 degrees.

Electrical Connections and Basing

The bottom view of the base provides the following pin connections:

The direct interelectrode capacitance between the external conductive coating and the anode is rated as:

• Maximum: 2,000 μμf
• Minimum: 750 μμf

Maximum Ratings (Design Center Values)

The operating limits of the 16ZP4 are defined by the following Design Center Values. Operating the tube beyond these limits may impair performance or cause permanent damage.

• Heater Voltage: 6.3 Volts
• Heater Current: 0.6 Ampere
• Maximum DC Anode Voltage: 16,000 Volts
• 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 period ≤ 15 seconds): 410 Volts
  • Heater negative with respect to cathode (after equipment warm-up): 125 Volts
  • Heater positive with respect to cathode: 125 Volts

Typical Operating Conditions and Characteristics

Under typical operating conditions, the 16ZP4 is configured with the following electrical and magnetic parameters:

• DC Anode Voltage: 12,000 Volts
• DC Grid No. 2 Voltage: 300 Volts
• DC Grid No. 1 Voltage: -33 to -77 Volts (for visual extinction of the undeflected focused spot)
• DC Focusing Coil Current: Approximately 110 mA. This value is specified using a standard focus coil #109 or equivalent, with the combined Grid No. 1 bias and video signal adjusted to produce a highlight brightness of 20 foot-lamberts on a 10-1/4" x 14-1/2" (or 10-1/8" x 14-1/2") picture. The distance from the reference line to the center of the focus coil air gap is 3.25 inches.
• DC Ion Trap Current: Approximately 120 mA when using a standard double field ion trap coil #108.

Circuit Constraints

• Maximum Grid No. 1 Circuit Resistance: 1.5 Megohms

Deflection and Focusing

The 16ZP4 employs magnetic deflection and magnetic focusing. The nominal deflection angle is approximately 52 degrees. The external double field ion trap must be adjusted to prevent ion burn on the phosphor screen and to maximize raster brightness.

Technical Summary

The 16ZP4 is a 15-7/8 inch round glass cathode-ray picture tube designed for television applications. It features magnetic focus and deflection with a 52-degree deflection angle, a unipotential cathode, and a white-emitting No. 4 phosphor screen with medium persistence. Operating at a typical anode voltage of 12,000 Volts (with a maximum rating of 16,000 Volts), the tube requires an external double field ion trap and a standard focusing coil to achieve optimal focus and brightness. Its electrical interface is provided via a 5-pin small shell duodecal base and a recessed small cavity cap for the high-voltage anode.