Phase detection circuit

The phase detection circuit is mainly composed of IC1 (dual voltage comparator LM319) and IC2 (double D flip-flop C013), as shown in the figure. This circuit has the advantages of simple structure, high accuracy and strong anti-interference ability. In the low frequency range of 0~30kHz, the detection accuracy is better than 0.1o. The circuit output signal can be directly connected to the computer interface or connected to a digital voltmeter through a low-pass filter, thus forming an ideal phase detector.