Microscopic verification of sensitive circuits of a quartz resonator applied in dew point recognition

This paper is aimed to carry out experimental verification of sensitive circuits of a quartz resonator applied in dew point recognition and it is proven at a microscopic level to be feasible in dew point recognition with great reliability and accuracy by using the high speed video. The sensor based on the sensitive circuits of a quartz resonator is composed of a quartz crystal and a Peltier module. Proactive approach is taken to produce condensation on the surface of the quartz crystal. The electrical parameters of the quartz crystal is changed due to dew condensation and then the resonant circuit stops oscillating. Initially, it needs to analyze the oscillation circuit and electrical characteristics of the quartz crystal, and then take photos of the surface of quartz electrodes with the high speed camera and microscope. Gray statistics is made for images of dew formation in its whole process. When the statistical results are analyzed in comparison to oscillation of the circuit, it shows that the time of the circuit oscillation stopping is roughly consistent with the time when moisture condensation occurs on the surface of the quartz electrode. And the time error of the two phenomena is less than 0.5 s, which is much less than response time of the platinum resistance sensor to the temperature. Furthermore, the results provide a strong theoretical basis for further measurement of the dew point temperature by this recognition method.