| 摘要 |
PROBLEM TO BE SOLVED: To provide a humidity detecting circuit, configured to measure a relative humidity by a humidity-sensing element, having a simple structure with a reduced number of components and being capable of prolonging the lifetime of the humidity-sensing element. SOLUTION: The lifetime of the humidity-sensing element 1 is increased with a simple structure by preventing irreversible deterioration due to electrolysis, by: connecting the humidity sensing element 1 and a temperature sensing element 2 with temperature resistance characteristics equivalent to those of the humidity-sensing element 1 in series; applying a rectangular wave alternating voltage to the humidity sensing element 1, by shifting the output state of a first input/output means 4a and a second input/output means 4b of an single-chip microcomputer 7, which are connected to the humidity-sensing element 1 and the temperature sensing element 2, respectively; reading a divided voltage generated at the connection point 3a, between the humidity sensing element 1 and the temperature sensing element 2 by an A/D conversion reading means 6 of the single-chip microcomputer 7, to determine a value of the relative humidity; and keeping the first input/output means 4a and the second input/output means 4b, in a state of identical output voltage for a certain time period, such that a current is not applied to the humidity-sensing element 1. COPYRIGHT: (C)2011,JPO&INPIT
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