A capacitance type moisture sensor having the capability of accurately
detecting amounts of water is provided. This sensor has a sensor housing
having an electrically-insulating wall, a pair of electrodes disposed on
the sensor housing, and a circuit unit. An outer surface of the
electrically-insulating wall faces a space where the amounts of water
should be detected. On an inner surface of the electrically-insulating
wall, at least one of the electrodes is formed. An electric field
developed between the electrodes is defined as a moisture detecting
region. The circuit unit includes a capacitance detecting circuit for
detecting a capacitance value between the electrodes, which changes in
response to the amounts of water in the moisture detecting region, and an
output circuit for providing an electrical signal corresponding toe the
amounts of water according the capacitance value detected by the
capacitance detecting circuit.
