Digital hygrometer with capacitive sensor

An electronic hygrometer employing a capacitive sensor is described. This instrument gives a reading of relative humidity (RH) with an uncertainty of +or-2.0% at 20 degrees C and +or-3% from 10-60 degrees C over a range of 10-90% RH. This accuracy is achieved by the use of digital linearisation techniques and a separate temperature sensor to compensate for the temperature coefficient of the capacitive humidity sensor. A rapid response time of 1-2 s is achieved.