| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a liquid property detecting device precisely measuring concentration by eliminating an influence of a leakage resistance between electrodes in a capacitance type concentration sensor. <P>SOLUTION: A gain of an amplification circuit 40 is not fixed, can be switched, and is increased with a decrease of a voltage Vb being an ethanol concentration detection signal. With this structure, in a region in which a variation of a voltage V<SB>50</SB>corresponding to a variation of the ethanol concentration is small, that is, a region in which the voltage Vb satisfies the inequality 0<Vb<P, the voltage V<SB>50</SB>is increased by increasing the gain so as to raise the resolution. Thus, an ethanol concentration sensor accurately measuring ethanol concentration is provided. <P>COPYRIGHT: (C)2010,JPO&INPIT</p> |
