1AX2 — Half-Wave High-Voltage Rectifier

The 1AX2 is a half-wave high-voltage rectifier vacuum tube designed specifically for television flyback rectifier service. It is engineered to handle high inverse voltages and deliver rectified direct current to the high-voltage anode of a television picture tube.

Filament and Base Connections

The 1AX2 features a directly heated filament designed for low-voltage direct current (DC) operation. The physical layout utilizes a specific base configuration and outline standard.

• Filament Voltage (DC): 1.4 V
• Filament Current: 0.65 A
• Base Connections: 9Y
• Outline Drawing: 6-7

The filament is designed to operate at a nominal 1.4 V, drawing a current of 0.65 A. This low-voltage, high-current filament design is typical for rectifiers operating in high-voltage environments where isolation and efficient heating are required.

Electrical Characteristics and Tube Voltage Drop

In typical operation, the 1AX2 exhibits a characteristic internal voltage drop when conducting. This parameter is critical for determining the efficiency and heat dissipation of the tube during conduction.

• Typical Tube Voltage Drop: Approximately 200 V at a direct-current (d-c) flow of 7 mA.

This voltage drop represents the internal resistance of the tube under load and is a key factor in circuit design, particularly when calculating the overall efficiency of the high-voltage power supply.

TV Flyback Rectifier Ratings and Operating Conditions

The 1AX2 is primarily intended for television flyback rectifier service, where it must withstand extreme electrical stresses during the horizontal retrace period. The maximum ratings established for this service define the safe operating envelope of the device.

Maximum Ratings

• Maximum D-C Output Current: 0.5 mA
• Maximum Inverse Voltage (d-c component): 20,000 V
• Maximum Peak Current: 45 mA

Pulse Duration Constraints

In flyback rectifier service, the high-voltage pulses applied to the tube are periodic. To prevent damage and ensure reliable operation, the duration of the pulse voltage must not exceed 15 percent of one scanning cycle. This duty cycle limitation is essential for preventing excessive heating and voltage breakdown within the tube structure.

Technical Summary

The 1AX2 is a specialized half-wave high-voltage rectifier tube designed for television flyback circuits. Operating with a 1.4 V, 0.65 A DC filament, the tube is housed in an envelope utilizing a 9Y base connection scheme and a 6-7 outline. It is rated to withstand a maximum direct-current component of inverse voltage up to 20,000 V, with a maximum peak current of 45 mA and a maximum continuous direct-current output of 0.5 mA. Under typical conduction conditions, it exhibits a tube voltage drop of approximately 200 V at 7 mA. Its operation in pulsed high-voltage environments is constrained by a maximum pulse duration of 15 percent of a single scanning cycle.