| 摘要 |
PURPOSE:To enable compensation to humidity and temp., and to enable the detection of high concn. gas, by providing a gas sensitive element and a compensation element for forming a gas detecting bridge in predetermined constitution. CONSTITUTION:A semiconductor type gas detecting bridge 21 consists of series two arms 24 of a semiconductor type detection element 22 and a temp. and humidity compensating element 23 and series two arms 37 of fixed and variable resistance elements 35, 36. The detection element 22 constitutes a gas sensitive element 25 formed by applying tin oxide or other metal oxide semiconductors to a heat wire 26 comprising platinum. The compensating element 25 is constituted by providing a humidity pervious part 31 or a gas sensitive element 30 similar to the gas sensitive element 25. When a current is supplied to the series two arms 24, 37, the temps, of the elements 22, 23 are raised. When steam-containing gas is contacted with the elements 22, 23, semiconductor 28 adsorbs steam and gas to change the resistance of the detection element 22 while steam is adsorbed with the semiconductor 34 through the humidity pervious part 31 to change the resistance of the compensating element 23. Therefore, outputs, after humidity and temp. compensation is performed, are obtained at output terminals 40, 41. |
