Dew point and relative humidity measurement using a quartz resonant sensor

A new dew point measurement device for humidity measurement in high temperature environment using a quartz crystal sensor was proposed. Combined with Peltier module and quartz crystal, active condensation occurs in the quartz surface to change the mass on the surface of quartz crystal, and use the shift of its resonant frequency identify the time of condensation. This quartz sensor does not require any absorbent material, and it is directly stuck on the Peltier element. The sensor system can also be achieved relative humidity measurement based on dew point and ambient-temperature measuring. It can operate in the range of dew point temperature from 50 to −30 °C, and in the range of relative humidity from 1 to 90 % RH. The measured dew points values and relative humidity values showed very good agreement with reference values and were within ±0.3 °C, 1 % RH, respectively over the whole temperature range.