An Application of the Driving Circuit for Resistive Humidity Sensor using Timer IC to the Thermo-hygrometer

Abstract

The authors produced a driving circuit for resistive humidity sensor using the timer IC and applied it to the thermo-hygrometer. This paper describes as follows: (1) a simple driving circuit using the timer IC was produced and the theoretical equation of its oscillating frequency was derived. (2) relative humidity as low as 10 %RH could be measured using the driving circuit for resistive humidity sensor. (3) the measurement error of the thermo-hygrometer using the driving circuit was achieved within ± 3 %RH above 30 %RH.