The U4087B is a phase control circuit designed and manufactured by TEMIC Semiconductors (now Vishay). It's primarily used in applications that require precise control of AC power, such as dimming lights or controlling motor speed.

Applications

• Light dimming circuits
• Motor speed control
• Heater control
• Phase-controlled rectifiers
• Universal motor control

Features

• Phase control of AC voltage
• Adjustable firing angle
• Synchronized to AC line voltage
• Trigger output for Triac or Thyristor
• Internal voltage regulation

Benefits

• Precise control of AC power, allowing for smooth and accurate adjustment of light intensity, motor speed, or heater temperature.
• Versatility in controlling different types of loads, including resistive and inductive loads.
• Simplified circuit design due to the integrated functionality, reducing the number of external components required.
• Stable and reliable operation due to the internal voltage regulation, ensuring consistent performance despite variations in line voltage.
• Easy implementation with standard Triacs or Thyristors.

Additional Details

The U4087B uses the AC line voltage as a reference for phase angle control, ensuring synchronization with the AC waveform. The firing angle, which determines the amount of power delivered to the load, is adjustable using an external potentiometer or control voltage. The output trigger pulse is designed to drive a Triac or Thyristor, which switches the AC power to the load. The datasheet should be consulted for specific timing diagrams, recommended external component values, and application notes to ensure proper and safe operation. It typically operates from standard AC line voltages. The device's internal circuitry generates the necessary timing signals for precise phase control.