In industrial production, electrical connections are essential in various devices, and the instantaneous disconnection of electrical connections is a common failure situation in electronic circuit interconnections, while existing instruments and technologies monitor low contact instantaneous time accuracy, contact reliability and vibration resistance are poor. In this paper, an improved STM32-based transient detector detection system is proposed, which outputs the instantaneous and stable electrical signals to the comparator TLV3502 for comparison. The embedded STM32FI03 chip processor captures the output electrical signals of the comparator to calculate the transient jump time, and displays the measurement results through improved limiting lag filtering method, thus achieving high accuracy, fast speed and wide range of instantaneous measurements.