A Servo-Controlled stabilizer is an electrical device that automatically regulates and stabilizes output voltage, protecting connected equipment from voltage fluctuations like sags and surges. It operates on a closed-loop control system that continuously monitors the input voltage. When a deviation is detected, a microprocessor-based control circuit sends a signal to a servo motor. This motor then rotates a variable transformer, known as a dimmerstat or autotransformer, to either 'buck' (decrease) or 'boost' (increase) the voltage. . This precise, continuous adjustment ensures a stable output voltage with high accuracy, typically within a narrow tolerance of ±1%. Unlike traditional relay-based stabilizers that use discrete steps, the servo mechanism provides a smooth, stepless correction, making it ideal for protecting sensitive and expensive equipment in industrial, commercial, and medical applications.