19ZP4 — Electrostatic-Focus Glass Picture Tube
The 19ZP4 is a 19-inch rectangular glass picture tube designed for television display applications. It features electrostatic focusing and magnetic deflection, utilizing a short overall length and a small neck diameter to facilitate compact cabinet designs. The tube incorporates a non-ion trap gun and an external conductive coating that, when grounded, serves as a filter capacitor.
Mechanical Design and Screen Characteristics
The 19ZP4 is constructed with a J149-A1 glass bulb and uses a spherical gray faceplate. The screen is aluminized and utilizes P4 phosphor, providing a light transmittance of approximately 76% at the center.
Physical Dimensions
- Overall Length: 11 1/2 ± 5/16 inches
- Neck Length: 4 1/4 ± 3/16 inches
- Greatest Diagonal: 18 5/8 ± 1/8 inches
- Greatest Width: 16 13/32 ± 1/8 inches
- Greatest Height: 13 11/32 ± 1/8 inches
Screen Dimensions (Projected Minimum Useful)
- Diagonal: 17 9/16 inches
- Horizontal Axis: 15 1/8 inches
- Vertical Axis: 12 inches
- Total Area: 172 square inches
Deflection Angles (Approximate)
- Diagonal: 114°
- Horizontal: 102°
- Vertical: 87°
The tube is equipped with a JETEC No. B6-226 base and a JETEC No. J1-21 anode contact (Anode Terminal J1-J2). The recessed cavity contact for the anode is aligned with Pin No. 4 (or its reverse) within a tolerance of ±30 degrees.
Electrical Connections and Heater Ratings
The 19ZP4 uses the 8JS basing diagram. The electrical connections are assigned as follows:
Heater Characteristics
The heater is designed for nominal 6.3 V operation, drawing a current of 600 mA (with a tolerance of ±10%). The heater warm-up time is rated at 11 seconds.
Direct Interelectrode Capacitances
- Cathode to all other electrodes: Approximately 5 µµF
- Grid No. 1 to all other electrodes: Approximately 6 µµF
- External conductive coating to Anode: 1000 pF (µµF) minimum, 1500 pF (µµF) maximum
Operating Conditions and Design-Maximum Ratings
All voltages are positive and measured with respect to the cathode unless otherwise specified. Under the Design-Maximum System, the operating limits and typical operating points are defined as follows:
Design-Maximum Ratings
- Anode Voltage: 15,000 V minimum to 20,000 V maximum
- Grid No. 4 (Focusing Electrode) Voltage: -500 V to +1000 V maximum
- Grid No. 2 Voltage: 400 V minimum to 700 V maximum
- Grid No. 1 Voltage:
- Maximum Negative DC Value: 140 V
- Maximum Negative Peak Value: 200 V
- Maximum Positive DC Value: 0 V
- Maximum Positive Peak Value: 2 V
- Heater Voltage: 5.7 V minimum to 6.9 V maximum
- Maximum Heater-Cathode Voltage:
- Heater negative with respect to cathode (during warm-up ≤ 15 seconds): 410 V
- Heater negative with respect to cathode (after warm-up): 180 V
- Heater positive with respect to cathode: 180 V
Typical Operating Conditions
- Anode Voltage: 16,500 V DC
- Grid No. 4 Voltage: 250 V DC (Individual tubes focus satisfactorily within a range of 0 to 500 V DC)
- Grid No. 2 Voltage: 450 V DC
- Grid No. 1 Voltage: -28 to -72 V DC (for visual extinction of the focused raster)
Circuit Design and Resistance Limits
To ensure reliable operation and prevent damage to the tube's internal structures, specific circuit resistance limits must be observed:
- Grid No. 1 Circuit Resistance: 1.5 MΩ maximum
- Grid No. 2 Circuit Resistance: 0.1 MΩ minimum
- Focusing Electrode (Grid No. 4) Circuit Resistance: 0.1 MΩ minimum
It is advisable to include protective resistance in the Grid No. 2 and focusing electrode circuits to prevent damage from internal arc-overs. A single common resistor may be utilized for these protective functions where applicable.
Technical Summary
The 19ZP4 is a 19-inch rectangular glass picture tube featuring electrostatic focus, 114-degree magnetic deflection, and a P4 aluminized screen with a spherical gray faceplate. Operating at a nominal heater voltage of 6.3 V with an 11-second warm-up time, it is designed for high-voltage television display applications with typical anode operation at 16,500 V. Its mechanical design features a short overall length of 11 1/2 inches and a small neck diameter, while its electrical design incorporates a non-ion trap gun and an external conductive coating that functions as a filter capacitor when grounded.
