12ANP19 — Electrostatic Deflection and Focus Cathode-Ray Tube

The 12ANP19 is a 12-inch, direct-viewed, round glass-type cathode-ray tube (CRT) designed for oscilloscope applications. It features electrostatic deflection, electrostatic focus, post-deflection acceleration, and an aluminized screen. The 12ANP19 is specifically configured with the P19 phosphor screen, which provides orange fluorescence, orange phosphorescence, and long persistence, making it highly suitable for displaying slow-scan signals or transient waveforms.

Phosphor and Screen Characteristics

The 12ANP- series of cathode-ray tubes can be supplied with several different screen phosphors. The 12ANP19 variant is defined by its P19 phosphor screen. The primary characteristics of this screen include:

• Fluorescence: Orange
• Phosphorescence: Orange
• Persistence: Long
• Screen Type: Aluminized
• Minimum Useful Screen Diameter: 11 Inches

Other variants in the same family utilize alternative phosphors to suit different display requirements. For example, the P7 phosphor provides blue-white fluorescence, yellow phosphorescence, and long persistence; the P14 phosphor provides purple fluorescence, orange phosphorescence, and medium-long persistence; and the P25 phosphor provides orange fluorescence, orange phosphorescence, and long persistence.

Mechanical Specifications and Basing

The 12ANP19 is constructed with a round glass bulb and utilizes a Medium Shell Diheptal 12-Pin base (designation B12-37). High-voltage and deflection connections are made via specialized bulb and neck contacts.

Physical Connections and Alignment

• Base Type: B12-37
• Basing Configuration: 14AW
• Bulb Contact: Recessed Small Cavity Cap (J1-22)
• Neck Contacts: Small Ball Caps (J1-25)
• Bulb Contact Alignment: The J1-22 contact aligns with the D3-D4 trace within ±10 degrees, and with Pin No. 11 within ±10 degrees.
• Neck Contact Alignment: The neck contact (A2) aligns with the D1-D2 trace within ±10 degrees.

Deflection Geometry and Beam Behavior

• Deflection Plate Arrangement: Deflection plates 1 and 2 are positioned nearer to the screen than deflection plates 3 and 4.
• Trace Orthogonality: The angle between the D1-D2 trace and the D3-D4 trace is 90 ± 1 Degree.
• Deflection Direction:
  • A positive voltage applied to deflection plate D1 deflects the electron beam approximately away from the neck contact A2.
  • A positive voltage applied to deflection plate D3 deflects the electron beam approximately away from the post-accelerator button (J1-22).
• Undeflected Spot Position: The undeflected, focused spot falls within a 20 mm square centered on the tube face.

Electrical and Interelectrode Capacitances

The direct interelectrode capacitances of the 12ANP19 are approximately as follows:

Heater and Power Supply Requirements

The tube's electron gun is indirectly heated, requiring a stable heater supply:

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

Maximum Ratings (Absolute Maximum Values)

Operating the 12ANP19 beyond these absolute maximum limits may cause permanent damage or severely degrade performance.

Note on Anode Input: The anode input is defined as the product of the Anode No. 2 voltage and the average Anode No. 2 current.

Typical Operating Conditions

The following values represent typical operating parameters for the 12ANP19 in standard oscilloscope service:

• Anode No. 3 Voltage: 9,700 Volts DC
• Anode No. 2 Voltage: 6,100 Volts DC
• Anode No. 1 Voltage for Focus: 1,510 to 2,225 Volts DC
• Grid No. 1 Voltage Required for Cutoff: -135 to -202 Volts DC (defined as the voltage required for visual extinction of an undeflected focused spot)
• Focus Electrode Current: -25 to +25 µA
• Deflection Factors:
  • Deflecting Plates 1-2: 100 to 150 Volts DC/Inch
  • Deflecting Plates 3-4: 100 to 150 Volts DC/Inch
• Modulation: 45 Volts Max. (measured in accordance with MIL-E-1 specification at a post-accelerator current of 25 µA)
• Line Width "A": 0.5 mm (measured at a post-accelerator current of 25 µA)
• Line Width "B": 0.75 mm (measured at a post-accelerator current of 25 µA)

Circuit Design Constraints

To ensure stable operation and protect the tube's electrodes, the external circuit must adhere to the following maximum resistance limits:

• Grid No. 1 Circuit Resistance: 2.0 Megohms Max.
• Resistance in Any Deflection Plate Circuit: 5.0 Megohms Max.

Technical Summary

The 12ANP19 is a high-performance, 12-inch electrostatic deflection and focus cathode-ray tube featuring post-deflection acceleration and an aluminized screen with a long-persistence orange P19 phosphor. Designed for precision oscilloscope and display applications, it operates with a 6.3 V, 0.6 A heater and supports post-deflection accelerator voltages up to 16,000 V DC. With its well-defined deflection factors (100 to 150 V/inch), tight trace orthogonality (90 ± 1 degree), and controlled line widths, the 12ANP19 provides a reliable, high-resolution display solution for specialized electronic instrumentation.