| 摘要 |
PURPOSE:To operate stably even in high density gas by constituting a bridge circuit of a hot wire type semiconductor element, and an electric resistor which can disregard a resistance variation by Joule's heat. CONSTITUTION:A hot wire type semiconductor element 2 which is placed in a gas to be measured and whose element resistance and temperature are lowered by a high density detecting gas, and an electric resistor 12 which can disregard a resistance variation by Joule's heat are connected in series, a bridge circuit is formed together with resistances 6, 7, and a gas detecting output is fetched from the connecting point between the element 2 and the resistor 12, and a reference potential point by the resistances 6, 7. According to the constitution which has used a prescribed resistor without using the same compensating element as this element 2, a harmful positive feedback phenomenon such as the increase, etc. of the resistance of the compensating element based on a temperature rise due to the increase of a current in a high density gas is not generated, and the high density gas can also be detected stably with a good reproducibility. |
