19BDP4 — Rectangular Glass Picture Tube
The 19BDP4 is a rectangular glass picture tube designed for television display applications. It features an aluminized screen, low-voltage electrostatic focus, and magnetic deflection. The tube is engineered with a cathode-drive electron gun that operates without the need for an external ion-trap magnet.
Overview and Optical Characteristics
The 19BDP4 utilizes a rectangular glass envelope with a filterglass faceplate. The faceplate has a light transmission rating of approximately 78%, which helps improve picture contrast under ambient lighting conditions. The screen is coated with an aluminized P4-Sulfide Type phosphor, providing a bright and efficient display.
Key operational features of the 19BDP4 include:
- Deflection Angle: 92° magnetic deflection.
- Focusing Method: Low-voltage electrostatic focus.
- Electron Gun: Cathode-drive design requiring no ion-trap magnet.
- Operating Position: Unrestricted (any position).
Mechanical Specifications and Basing
The physical structure of the 19BDP4 is characterized by its rectangular screen and specific mechanical dimensions.
Physical Dimensions and Weight
- Overall Length: 15-1/4" ± 3/8"
- Neck Length: 5-1/2" ± 3/16"
- Projected Screen Area: 172 square inches
- Weight: Approximately 15 lbs
External Fittings and Connections
The tube features a regular band-type external conductive coating, which requires a grounding contact area located near the Reference Line. The high-voltage connection is made via a recessed small cavity cap (JEDEC No. J1-21).
The base of the tube can be one of two alternate configurations:
- A Short Small-Shell Duodecal 6-Pin base (JEDEC Group 4, No. B6-203).
- A Small-Shell Duodecal 6-Pin base, Arrangement 1 (JEDEC Group 4, No. B6-63).
The overall pin configuration is designated as the 12L basing arrangement, viewed from the bottom of the tube.
Pinout Configuration (12L Bottom View)
Heater and Electrical Characteristics
The 19BDP4 is designed with an indirectly heated cathode that features a controlled warm-up characteristic, making it suitable for series or parallel heater strings.
Heater Ratings
- Nominal Heater Voltage: 6.3 V
- Heater Current: 600 ± 10% mA
- Average Heater Warm-Up Time: 11 seconds
Interelectrode Capacitances
- Grid No. 1 to all other electrodes: 6 µµF
- Cathode to all other electrodes: 5 µµF
- External conductive coating to ultor: 1500 µµF (minimum) to 2000 µµF (maximum)
Design-Maximum Ratings
The design-maximum ratings represent the absolute limiting values for the safe and reliable operation of the 19BDP4. These ratings must not be exceeded under any operating conditions.
- Ultor-to-Grid-No. 1 Voltage: 12,000 V (minimum) to 19,800 V (maximum)
- Grid-No. 4-to-Grid-No. 1 (Focusing) Voltage:
- Positive value: 1100 V (maximum)
- Negative value: 500 V (maximum)
- Grid-No. 2-to-Grid-No. 1 Voltage: 40 V (minimum) to 70 V (maximum)
- Cathode-to-Grid-No. 1 Voltage: 100 V (maximum)
- Heater Voltage: 5.8 V (minimum) to 7.0 V (maximum)
- Peak Heater-Cathode Voltage:
- Heater negative with respect to cathode:
- During equipment warm-up period (≤ 15 seconds): 410 V (maximum)
- After equipment warm-up period: 180 V (maximum)
- Heater positive with respect to cathode: 180 V (maximum)
- Maximum Grid-No. 1-Circuit Resistance: 1.5 MΩ
Typical Operating Conditions
Under typical operating conditions, the 19BDP4 is set up with the following electrode potentials to achieve a focused raster and proper visual extinction:
- Ultor-to-Grid-No. 1 Voltage: 14,500 V
- Grid-No. 2-to-Grid-No. 1 Voltage: 50 V
- Grid-No. 4-to-Grid-No. 1 Voltage for Focus: 0 to 500 V
- Cathode-to-Grid-No. 1 Voltage for Visual Extinction of Focused Raster: 31 to 49 V
The low-voltage electrostatic focus design allows the focusing electrode (Grid No. 4) to be operated at or near ground potential, with a range of 0 to 500 V relative to Grid No. 1, simplifying the focus supply circuitry in television receivers.
