In this work is presented PSpice circuit models of hydrogen gas nanosensor using individual zinc oxide nanowire with fast response at room temperature and of an individual ZnO microwire-based ultraviolet (UV) photodetector. The model of hydrogen nanosensor depicts the dynamic response to 100 ppm gas concentration at room temperature and influence of the UV irradiation on electrical resistance of the material. The model of photodetector depicts the transient response to UV light (365 nm) and variation of the electrical resistance in the dark and under UV illumination for different relative humidity RH values. The models have been studied using Cadence software student version, and are based on the physical and chemical proprieties of the metal oxide sensing material.