16AEP4 Cathode Ray Tube

The 16AEP4 is a direct-view picture tube designed specifically for television applications. It features a rectangular glass construction, electrostatic focusing, magnetic deflection, and a grey filter faceplate. The design incorporates an external conductive coating, requires an external single-field ion trap magnet, and provides a nominal raster size of 10 1/8 by 13 1/2 inches.

Mechanical Design and Physical Dimensions

The 16AEP4 is constructed with a rectangular glass bulb and a specialized faceplate designed to optimize picture quality and contrast. The faceplate is a grey filter type with a light transmission of approximately 66 percent at the center.

The physical dimensions of the tube are precisely specified to ensure proper mounting and alignment within television receivers:

The tube uses a recessed small cavity cap (J1-21) for its high-voltage anode connection. The base is a small shell duodecal 6-pin (B6-63), which utilizes the 12M basing arrangement. The alignment of the J1-21 bulb contact is designed to align with pin position #3 within a tolerance of ±10 degrees.

A specific region along the neck of the tube, measuring 3 5/8 ± 1/16 inches from the reference line, must be kept clear to accommodate the external ion trap magnet. The distance from the reference line to the anode terminal is 3 5/8 ± 3/8 inches, while the distance from the reference line to the front face of the bulb is 11 1/4 ± 3/16 inches.

Electrical Characteristics and Pin Connections

The 16AEP4 features an indirectly heated, unipotential cathode. The electrical connections are distributed across the 6-pin duodecal base and the recessed cavity cap as follows:

Interelectrode Capacitances

The direct interelectrode capacitances of the tube are approximately:

• Cathode to all other electrodes: 5.0 µµf
• Grid No. 1 to all other electrodes: 6.5 µµf

Additionally, the external conductive coating forms a capacitance with the internal anode. The capacitance values are:

• Maximum external conductive coating to anode: 1,500 µµf
• Minimum external conductive coating to anode: 750 µµf

Electro-Optical and Deflection Characteristics

The 16AEP4 utilizes magnetic deflection with an approximate diagonal deflection angle of 70 degrees. The focusing system is electrostatic, controlled via Grid No. 4.

The screen is coated with Phosphor No. 4, which exhibits the following optical properties:

• Fluorescent Color: White
• Phosphorescent Color: White
• Persistence: Medium

To prevent ion burn on the phosphor screen, the tube requires an external single-field ion trap magnet. Under typical operating conditions, this magnet is energized by a standard coil (such as Standard Coil #111) carrying an approximate DC current of 75 ± 50% mA.

Operating Points and Ratings

The operating limits of the 16AEP4 are defined under the Design Center rating system. Designers must adhere to these maximum ratings to ensure reliable operation and longevity of the tube.

Design Center Maximum Ratings

Heater-Cathode Voltage Limits

The maximum peak heater-cathode voltage depends on the polarity and the operating state of the equipment:

• Heater negative with respect to cathode:
  • During warm-up period (not to exceed 15 seconds): 410 Volts
  • After equipment warm-up period: 125 Volts
• Heater positive with respect to cathode: 125 Volts

The cathode should be returned to one side or to the mid-tap of the heater transformer winding to minimize potential differences and hum.

Typical Operating Conditions

Under typical operating conditions, the tube is configured with the following electrical parameters:

The focusing voltage applied to Grid No. 4 can be adjusted within the range of -64 to +350 Volts to achieve a sharp, well-defined spot on the screen. The Grid No. 1 voltage required to achieve visual extinction of an undeflected focused spot ranges from -33 to -77 Volts.

Technical Summary

The 16AEP4 is a 70-degree magnetic deflection, electrostatic-focus cathode ray tube designed for direct-view television applications. It features a rectangular glass envelope, a grey filter faceplate with 66% light transmission, and a No. 4 white phosphor screen of medium persistence. Operating with a nominal 6.3 V, 0.6 A heater, the tube is rated for a maximum anode and Grid No. 3 voltage of 16,000 V, with a typical operating point of 14,000 V. It utilizes a small shell duodecal 6-pin base (B6-63) with a 12M basing configuration and a recessed small cavity cap (J1-21) for the high-voltage anode connection. Proper operation requires an external single-field ion trap magnet and careful adherence to the specified heater-cathode voltage limits and grid circuit resistance constraints.