A method to get perfect balance point of differential eddy current displacement sensors

Abstract This study introduces a novel method to increase the stability of the balance point in precision differential eddy current sensor (ECS) displacement sensors, which is crucial for achieving optimal performance and improving the interchangeability of sensor probes. The temperature drift coefficient at the electrical balance point (BTC), a common issue affecting the accuracy and reliability of measurements, is addressed through our approach. The BTC can be accurately adjusted by fine-tuning the length of the aluminum target, which aligns the zero-temperature drift position with the electrical balance position, thereby achieving a perfect balance point. The experimental results demonstrate that the proposed method significantly reduces the temperature drift near the balance point of the differential ECS. The BTC was effectively reduced from −7.21 nm/°C to 0.22 nm/°C. This substantial reduction in the BTC enhances the stability of the sensor, facilitating more reliable measurements in high-precision applications.