| 摘要 |
<p>A gas detecting method and a device therefor, wherein the time needed from the time the power is turned on till gas detection becomes possible is short. A microcomputer (5) delivers a pulse signal to cause the on-duty of a transistor (Q1) to be 75 ν sec from an exhaled gas detection to reduce the average voltage to be applied to a heater (2) and causes the temperature of a metal oxide semiconductor gas sensor (3) to shift to a lower-temperature heating state. The resistance value of a gas sensor sampled at the point of time this shifting is started is stored in a built-in RAM as a reference resistance value RO', and ratios Rs/RO' are computed where Rs is a resistance value found by sampling thereafter every 0.5 sec. And the ratio of the calculated value obtained 2 sec after the start of low temperature heating state shift, to the reference value (Rs/RO) found in the adjustment mode is found, on the basis of which ratio the degree of halitosis is determined and a character corresponding to the determined degree of halitosis is displayed on an LCD (4).</p> |
