19BRP4 — 19-Inch Cathode Ray Tube

Overview

The 19BRP4 is a 19-inch, 114-degree lightweight cathode ray tube (CRT) designed primarily for television display applications. It features a laminated construction with a Pittsburgh facepanel and a short neck length of 4 3/8 inches. The tube utilizes electrostatic focusing and magnetic deflection, incorporating a metal-backed (aluminized) screen with a straight electron gun that does not require an external ion trap.

Physical Construction and Optical Characteristics

The 19BRP4 is built using a laminated structure that incorporates a Pittsburgh facepanel and an FP149A1 implosion panel, resulting in an approximate weight of 18 lbs. The bulb conforms to the EIA designation C-149 Exp. #5 or its equivalent.

The optical system features an aluminized P4 phosphor screen, which provides a metal-backed reflective layer to maximize light output. The light transmittance at the center of the facepanel is approximately 52%.

The physical dimensions and mechanical specifications include:

• Deflection Angle: 114 degrees
• Neck Length: 4 3/8 inches
• Bulb Contact (Ultor): JEDEC J1-21
• Base: JEDEC B7-208
• Basing Arrangement: JEDEC 8HR
• Implosion Panel: FP149A1
• Approximate Weight: 18 lbs

Electrical Connections and Pinout

The 19BRP4 uses the JEDEC B7-208 base with the JEDEC 8HR basing configuration. The electrical connections are assigned as follows:

The heater is designed for a nominal voltage of 6.3 V and operates at a current of 600 ± 5% mA. The heater warm-up time is approximately 11 seconds.

Direct Interelectrode Capacitances

The capacitive coupling between the internal electrodes and external coatings is characterized by the following values:

• Cathode to all other electrodes: ~5 μμf
• Grid #1 to all other electrodes: ~6 μμf
• External conductive coating to anode: 1000 μμf (minimum) to 1500 μμf (maximum)

Electrical Ratings and Operating Conditions

The 19BRP4 is rated under the design-maximum system. These ratings represent the absolute limits within which the tube must be operated to ensure reliability and performance.

Design-Maximum Ratings

• Anode Voltage: 12,000 V (minimum) to 23,000 V (maximum)
• Grid #4 (Focusing Electrode) Voltage: -550 V to +1100 V
• Grid #2 Voltage: 550 V (maximum)
• Grid #1 Voltage:
  • Maximum Negative DC Value: 155 V
  • Maximum Negative Peak Value: 220 V
  • Maximum Positive DC Value: 0 V
  • Maximum Positive Peak Value: 2 V
• Heater Voltage: 5.7 V (minimum) to 6.9 V (maximum)
• Heater-Cathode Voltage:
  • Heater negative with respect to cathode (during warm-up ≤ 15 seconds): 450 V (maximum)
  • Heater negative with respect to cathode (after warm-up): 200 V (maximum)
  • Heater positive with respect to cathode: 200 V (maximum)
• Maximum Grid #1 Circuit Resistance: 1.5 Megohms

Typical Operating Conditions (Grid Drive Service)

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

• Anode Voltage: 16,000 V DC
• Grid #4 Voltage (Focusing Electrode): 0 to +400 V DC
• Grid #2 Voltage: 300 V DC
• Grid #1 Voltage (for visual extinction of focused raster): +35 to +72 V DC

Safety Considerations

When operating the 19BRP4 at high anode voltages, safety precautions regarding X-ray radiation must be observed. If the tube is operated at anode voltages exceeding 16,000 V, shielding may be necessary to protect users against prolonged exposure to X-ray radiation at close range.

Technical Summary

The 19BRP4 is a 19-inch, 114-degree cathode ray tube featuring a lightweight, laminated construction with a Pittsburgh facepanel and an FP149A1 implosion panel. It utilizes electrostatic focusing via Grid #4 and magnetic deflection, operating with a straight electron gun and an aluminized P4 phosphor screen. The nominal heater rating is 6.3 V at 600 mA with an 11-second warm-up time. Designed for grid drive service, it operates typically at an anode voltage of 16,000 V DC, with Grid #4 focusing voltage adjustable from 0 to +400 V DC, and Grid #2 at 300 V DC. The design-maximum anode voltage limit is 23,000 V, and appropriate X-ray shielding is recommended if operated above 16,000 V.