Sensing Circuit

A sensing circuit is an electronic component within protection relays and power transistors that continuously monitors electrical parameters such as current, voltage, temperature, or frequency. It converts these physical quantities into measurable electrical signals, processes them through comparators or amplifiers, and outputs control signals to activate protective mechanisms when predefined thresholds are exceeded, preventing equipment damage and ensuring operational safety.

The sensing circuit operates by using sensors (like current transformers, voltage dividers, or thermistors) to detect electrical parameters. These signals are conditioned through filtering, amplification, and analog-to-digital conversion. The processed data is compared against preset thresholds by operational amplifiers or microcontrollers. When abnormal conditions are detected (e.g., overcurrent, undervoltage), the circuit triggers output signals to disconnect power, activate alarms, or adjust transistor switching, based on electromagnetic or solid-state relay logic.