19WP2 — Character-Display Cathode-Ray Tube

The 19WP2 is a specialized 19-inch metal-cone cathode-ray tube (CRT) designed to display characters and letters ranging in size from 3/8 inch to greater than 1 inch. These symbols are typically generated by monoscope tubes or symbol generators and are displayed on a small, 1/2-inch square raster area. This raster can be positioned anywhere on the screen using an external magnetic deflection yoke. The tube features electrostatic focusing, combined electrostatic and magnetic deflection, a gray filter-glass faceplate, and a metal-backed screen.

Optical and Phosphor Characteristics

The 19WP2 is equipped with a metal-backed screen utilizing Phosphor No. 2, which has the following characteristics:

• Fluorescent Color: Blue-Green
• Phosphorescent Color: Green
• Persistence: Long
• Faceplate Light Transmission: Approximately 55% at the center of the gray filter-glass faceplate

Mechanical Design and Alignment

The physical structure of the 19WP2 is designed to accommodate both internal electrostatic deflection plates and external magnetic deflection components.

• Overall Length: 24-11/16 ± 3/8 inches
• Greatest Bulb Diameter: 18-5/8 ± 1/8 inches
• Minimum Useful Screen Diameter: 17-3/8 inches
• Neck Length: 10-5/16 ± 3/16 inches
• Maximum Neck Outer Diameter: 1.500 inches (including deflection connections)
• Deflection Plate Connections: J1-25 contacts located on the neck
• Base: Small Shell 7-Pin Duodecal (B7-51) with a 12AV basing configuration

Deflection and Trace Alignment

• Base Alignment: The trace produced by the D3D4 deflection plates aligns with Pin No. 2 and the tube axis within ± 30 degrees.
• Trace Angle: The angle between the D3D4 and D1D2 traces is 90 ± 2 degrees.
• Deflection Direction: A positive voltage on D1 deflects the beam approximately toward Pin No. 5. A positive voltage on D3 deflects the beam approximately toward Pin No. 2.
• Magnetic Deflection Field: The external magnetic deflection field must be positioned such that it does not extend below line "B" on the neck.

Electrical Connections and Pinout

The 12AV basing arrangement provides the following pin connections:

Heater Ratings

• Heater Voltage: 6.3 V
• Heater Current: 0.6 A ± 10%

Direct Interelectrode Capacitances

The approximate capacitances of the tube electrodes are:

• Cathode to all other electrodes: 4.0 μμf
• Grid No. 1 to all other electrodes: 5.0 μμf
• Deflection Plate D1 to Deflection Plate D2: 1.6 μμf
• Deflection Plate D3 to Deflection Plate D4: 1.6 μμf
• Deflection Plate D1 to all other electrodes: 2.5 μμf
• Deflection Plate D2 to all other electrodes: 2.5 μμf
• Deflection Plate D3 to all other electrodes: 2.5 μμf
• Deflection Plate D4 to all other electrodes: 2.5 μμf

Design Maximum Ratings

The following maximum ratings are specified under the Design Maximum Rating System:

• Accelerator Voltage: 13,200 Max VDC
• Accelerator Input: 6 Max Watts
• Focusing Electrode Voltage: 6,000 Max VDC
• Grid No. 2 Voltage: 770 Max VDC
• Grid No. 1 Voltage:
  • Negative Bias Value: 200 Max VDC
  • Positive Bias Value: 0 Max VDC
  • Positive Peak Value: 0 Max V
• Peak Heater-Cathode Voltage:
  • Heater negative (during warm-up ≤ 15 seconds): 410 Max V
  • Heater negative (after warm-up): 180 Max V
  • Heater positive: 180 Max V
• Peak Voltage between Accelerator and any Deflection Electrode: 550 Max V

Typical Operating Conditions

The 19WP2 can be operated under different accelerator voltage levels. The table below details typical operating parameters at 10,000 VDC and 7,500 VDC:

General Operating Characteristics

• Focusing Electrode Current: -15 to +10 μA
• Spot Position (focused and undeflected): Centered within a 25-mm square on the faceplate.
• Guide for other Accelerator Voltages:
  • Focusing Electrode Voltage: 34% to 46% of the Accelerator Voltage.
  • D1D2 Deflection Factor: 17 to 21 VDC/Inch per kilovolt (kV) of Accelerator Voltage.
  • D3D4 Deflection Factor: 16 to 20 VDC/Inch per kilovolt (kV) of Accelerator Voltage.

Maximum Circuit Values

To maintain operating stability, the external circuit resistances must be kept within the following limits:

• Grid No. 1 Circuit Resistance: 1.5 Max Megohms
• Deflecting-Electrode Circuit Resistance: 5.0 Max Megohms (it is recommended that approximately equal resistances be used in the deflecting-electrode circuits).

Technical Summary

The 19WP2 is an electrostatic-focus, electrostatic-deflection, and magnetic-deflection cathode-ray tube designed for character and symbol display. Featuring a 19-inch metal cone, a long-persistence green Phosphor No. 2 screen, and a gray filter-glass faceplate, it is optimized for displaying small, high-resolution characters generated by monoscopes or symbol generators. The tube operates with a standard 6.3 V, 0.6 A heater and supports accelerator voltages up to 13,200 VDC. Its dual-deflection design allows high-speed electrostatic character generation on a small raster, which can then be positioned across the screen using external magnetic deflection.