| 摘要 |
PROBLEM TO BE SOLVED: To provide a heater for gas detecting sensor which can maintain a detecting section at an appropriate temperature and a power controller which supplies electric power to the heater. SOLUTION: A measurement electrode 17" which connects one end of a heating section to a detection terminal 23a is formed in a sensor 7. Because of the electrode 17", the voltage at the heating section can be measured without being affected by the resistance values Re of lead sections 15a and 15c, etc. On the other hand, a power controller A is provided with a power supplying section 31 and commanding section 33 and the section 33 turns off the transistor TR1 of the section 31 when voltages Vc and V1 become equal to each other. The section 33 turns off the transistor TR1 a fixed period of time after. The circuit of the commanding section 33 is constituted so that the voltages Vc and V1 can become equal to each other when the resistance value Rh of the heating section becomes the value Ra corresponding to the target temperature of the heating section. Therefore, the heating section, in turn, the detecting section can be maintained at a desired temperature. |
