| 摘要 |
PURPOSE:To obtain a gas detecting element of simple structure which has small base temperature variation and, therefore, has small variation in output with temperature by covering a heating body which has a positive resistance temperature coefficient with a gas sensitive semiconductor which has a negative resistance temperature coefficient and thus constituting a two-terminal structure. CONSTITUTION:The heating body 12 which is made of a spiral Pt vapor-deposited film and serves as an electrode is provided to the outer circumference of a cylindrical support 11 which has, for example, heat-resisting and electric insulating properties. Then the outer circumference of the heating body 12 is covered with metal oxide such as SnO2 in contact to form the gas sensitive semicondutor 13, and lead wires 14 and 15 are connected to the terminal of the heating body 12 and the terminal of the semiconductor 13 to obtain a two-terminal semiconductor gas sensitive element S. A power source E is connected to the element S, whose output is detected by a detector V. The heating body 12 has the positive resistance temperature coefficient and the semiconductor 13 has the negative resistance temperature coefficient, so variations due to temperature variations in the resistance of the element S cancel each other at both terminals of the element S, thus obtaining the element S which has small output variation with temperature.
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