10AJP4 — Electrostatic Focus Cathode Ray Tube
A 10-inch rectangular, all-glass cathode ray tube featuring magnetic deflection, automatic electrostatic focus, and an aluminized white phosphor screen for display applications.
Overview
The 10AJP4 is a 10-inch rectangular cathode ray tube (CRT) designed for reliable display systems. It features a straight electron gun design with automatic electrostatic focusing, which eliminates the need for an external, adjustable focus power supply. The tube utilizes magnetic deflection with a nominal diagonal deflection angle of 90 degrees.
The "P4" designation specifies the use of a standard white-emitting phosphor screen. This screen is fully aluminized to maximize light output and prevent screen charging effects during operation. To enhance display contrast under ambient lighting, the tube is constructed with a gray filter glass faceplate offering approximately 80% light transmission.
Mechanical Design and Physical Dimensions
The 10AJP4 is built around an all-glass rectangular envelope (bulb number J83-A1) with a robust mechanical structure. The physical dimensions and alignment tolerances are tightly controlled to facilitate precise mounting in display chassis:
- Overall Length: 10-7/8 ± 5/16 inches
- Neck Length: 5-1/2 ± 3/16 inches
- Greatest Bulb Dimensions:
- Diagonal: 10-3/8 ± 1/8 inches
- Width: 9-3/4 ± 1/8 inches
- Height: 7-1/2 ± 1/8 inches
- Minimum Useful Screen Dimensions: 9-1/16 × 6-5/8 inches
- Approximate Weight: 4 pounds
The tube features a recessed small cavity bulb contact (J1-21) for the high-voltage anode connection. This contact is aligned on the same side as pin number 6 of the base, with an alignment tolerance of ±30 degrees relative to the vacant pin 6 position. The reference line of the envelope is determined by the point where a JEDEC G-126 reference gauge stops.
Electrical Characteristics and Basing
The 10AJP4 utilizes an indirectly heated cathode. The heater is designed for AC or DC operation, and the tube features low direct interelectrode capacitances, which minimizes loading on drive circuitry.
Heater and Capacitance Ratings
Basing Configuration
The tube uses a Small Shell Duodecal 5-Pin base (B5-57) with a 12-S basing arrangement. The electrical connections, viewed from the bottom of the base, are assigned as follows:
Typical Operating Conditions and Performance
Under typical operating conditions, the focusing electrode is internally connected to Grid No. 2, simplifying external circuitry by removing the need for a dedicated focus voltage source. This configuration provides excellent focus across the entire screen at normal drive levels.
The typical operating parameters and performance metrics are defined as follows:
- Anode Voltage: 16,000 V DC
- Grid No. 2 Voltage: 300 V DC
- Grid No. 1 Voltage (for visual extinction of focused raster): -35 to -72 V DC
- Spot Position: The undeflected and focused spot will fall within a 1/4-inch radius circle concentric with the physical center of the tube face, provided the tube is adequately shielded from external magnetic and electrical influences.
- Line Width: Typically 0.010 inch, measured at an anode current of 100 µAdc.
- Resolution Capability: The tube is capable of resolving a minimum of 600 lines, ensuring high-definition rendering of text and graphics.
Maximum Ratings and Circuit Limits
The following limits are specified under the Design Maximum Rating System. Operating the tube beyond these limits may impair reliability or cause permanent damage.
Electrode Voltage Limits
- Anode Voltage: 20,000 V DC maximum
- Grid No. 2 Voltage: 550 V DC maximum
- Grid No. 1 Voltage:
- Negative Bias Value: 155 V DC maximum
- Positive Bias Value: 0 V DC maximum
- Positive Peak Value: 2 V maximum
Heater-Cathode Voltage Limits
To prevent insulation breakdown between the heater and the cathode, the potential difference must be kept within the following limits:
- Heater Negative to Cathode:
- During the 15-second warm-up period: 450 V maximum
- After warm-up: 200 V maximum
- Heater Positive to Cathode: 200 V maximum
Circuit Impedance Limits
- Grid No. 1 Circuit Resistance: 1.5 Megohms maximum
Related Phosphor Designations
The 10AJP- family of cathode ray tubes is available with alternative phosphor screens to suit different display requirements. While the 10AJP4 features a medium-persistence white screen optimized for standard television and general-purpose displays, other variants include:
- 10AJP7: Features a long-persistence screen with white fluorescence and yellow phosphorescence, suitable for radar or slow-scan applications.
- 10AJP31: Features a medium-short persistence screen with yellow-green fluorescence and yellow-green phosphorescence, optimized for high-contrast visual displays and photographic recording.
These variants share identical mechanical dimensions, basing, and electrical ratings, differing only in their optical persistence and emission color characteristics.
Technical Summary
The 10AJP4 is a 10-inch rectangular, magnetic deflection CRT featuring an automatic electrostatic focus straight gun and a fully aluminized P4 white phosphor screen. Operating at a typical anode voltage of 16,000 V DC and a Grid No. 2 potential of 300 V DC, it delivers a typical line width of 0.010 inch and is capable of resolving at least 600 lines. Its design simplifies system integration by internally connecting the focusing electrode to Grid No. 2, eliminating the need for an external focus supply. Housed in a J83-A1 glass bulb with a B5-57 Duodecal 5-pin base, the 10AJP4 provides a robust, high-resolution display solution within a compact 10-7/8 inch overall length.
