Abstract:

In order to further study the humiditysensitive characteristics of the humidity sensor, base on conductive mechanism, we adopt the complex impedance analysis method to research the humidity-sensitive characteristics of the humidity sensor. We design an effective impedance measurement circuit based on the principle of vector. The complex impedance of the humidity sensor in different humidity can be measured through the circuit. The complex impedance of the humidity sensor can also be measured in the different frequency of signal. The whole measuring system is mainly composed of a programmable signal source and phase sensitive detection circuit. The circuits are respe
ctively achieved by the DDS(Direct Digital Synthesizer)technology and analog multiplier. The structure is simple, easy to implement. The experiment results show that the whole system is feasible.

Key words: humidity sensor, principle of vector, phase sensitive detection, complex impedance measurement