16ANP4 — Television Picture Tube

The 16ANP4 is a 16-inch direct-viewed rectangular glass television picture tube designed for use in television receivers. It features a spherical faceplate with a bonded shield, electrostatic focusing, and 114-degree magnetic deflection. The tube utilizes an aluminized P4 phosphor screen that produces white fluorescence with medium-short persistence. It does not require an ion trap and includes an external conductive coating that must be grounded.

The 16ANP4 is closely related to the 16AQP4. Both tubes share identical electrical and mechanical specifications, except for the treatment of the safety plate. The 16ANP4 uses the FP125A safety plate, whereas the 16AQP4 features an anti-reflection treated safety plate designed to reduce specular reflection.

Construction and Physical Characteristics

The 16ANP4 is built with a J125A glass bulb and a laminated gray filter glass safety plate (FP125A) bonded directly to the face of the tube. This faceplate assembly provides a light transmittance of approximately 60 percent.

Mechanical Dimensions

• Minimum Useful Screen Dimensions:
  • Height: 10 1/4 inches
  • Width: 12 3/4 inches
  • Diagonal: 14 7/8 inches
  • Area: 125 square inches
• Neck Length: 4 1/8 ± 1/8 inches
• Overall Length: 10 7/16 ± 3/8 inches
• Weight (Approximate): 9 1/2 pounds

Deflection and Focusing

The tube employs electrostatic focusing and magnetic deflection. The deflection angles are approximately:

• Horizontal: 103 degrees
• Diagonal: 114 degrees
• Vertical: 88 degrees

Connections and Basing

The 16ANP4 uses a B7-208 base with an 8HR basing configuration. The high-voltage anode connection is made via a recessed small cavity cap (J1-21).

The pin connections (viewed from the bottom of the base) are:

• Pin 1: Heater
• Pin 2: Grid No. 1
• Pin 3: Grid No. 2
• Pin 4: Grid No. 4 (Focusing Electrode)
• Pin 6: Cathode
• Pin 7: Grid No. 1
• Pin 8: Heater
• Recessed Cap: Anode

Base pin No. 4 aligns with the vertical centerline (A-A') within 30 degrees and is located on the same side as the anode contact (J1-21). The reference line of the tube is determined by plane C-C' of the JEDEC No. 126 Reference Line Gauge when seated against the bulb.

Electrical and Heater Characteristics

The 16ANP4 features an indirectly heated cathode with the following nominal heater ratings:

• Heater Voltage: 6.3 Volts
• Heater Current: 0.60 ± 5% Ampere
• Heater Warm-up Time: 11 Seconds

The heater warm-up time is defined as the time required for the voltage across the heater to reach 80% of its rated value when four times the rated heater voltage is applied to a circuit consisting of the tube heater in series with a resistance. This series resistance is calculated as: $\text{Series Resistance} = 3 \times \frac{\text{Rated Heater Voltage}}{\text{Rated Heater Current}}$ Using the nominal values, this series resistance is: $3 \times \frac{6.3\text{ V}}{0.60\text{ A}} = 31.5\ \Omega$

Direct Interelectrode Capacitances

• Cathode to all other electrodes: 5 pF (approximate)
• Grid No. 1 to all other electrodes: 6 pF (approximate)
• External conductive coating to anode: 800 pF minimum to 1200 pF maximum

The external conductive coating must be grounded to serve as a high-voltage filter capacitor in conjunction with the internal conductive coating.

Operating Modes and Maximum Ratings

The 16ANP4 can be operated in either Grid Drive Service or Cathode Drive Service. The maximum ratings are established under the Design Maximum Rating System.

Grid Drive Service Ratings and Typical Operation

In Grid Drive Service, control signals are applied to Grid No. 1 while the cathode is typically held at a reference potential.

Cathode Drive Service Ratings and Typical Operation

In Cathode Drive Service, control signals are applied to the cathode while Grid No. 1 is typically held at a reference potential.

Cutoff Characteristics

The cutoff voltages specified above are for the visual extinction of a focused raster. For the cutoff of an undeflected focused spot, the absolute value of the bias between the cathode and Grid No. 1 increases by approximately 5 volts. This means the cutoff range shifts to approximately -38 to -75 V dc for Grid Drive, and +36 to +62 V dc for Cathode Drive.

Peak Heater-Cathode Voltage Ratings

The heater-to-cathode voltage limits are identical for both Grid Drive and Cathode Drive services:

• Heater Negative with Respect to Cathode:
  • During warm-up period (not to exceed 15 seconds): 450 Volts
  • After equipment warm-up period: 200 Volts
• Heater Positive with Respect to Cathode: 200 Volts

Circuit Values

The maximum allowable Grid No. 1 circuit resistance is 1.5 Megohms.

Safety and Operational Precautions

Because the 16ANP4 operates at high anode voltages, X-ray radiation shielding may be necessary to protect against potential personal injury from prolonged exposure at close range. This precaution is particularly critical if the tube is operated at voltages higher than the maximum rated anode voltage or 16,000 volts, whichever is less.

Additionally, the external conductive coating must be securely grounded to ensure safe operation and proper filtering of the high-voltage anode supply.

Technical Summary

The 16ANP4 is a 16-inch, 114-degree magnetic deflection television picture tube featuring electrostatic focusing, a bonded safety shield, and an aluminized P4 screen. It operates with a 6.3 V, 0.60 A heater and is designed for either Grid Drive or Cathode Drive service. With an anode voltage rating of up to 18,000 V dc, it provides a bright, high-contrast display suitable for direct-view television applications. The 16ANP4 is identical to the 16AQP4, with the latter featuring an anti-reflection treated safety plate.