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Application filed by Nohmi Bosai Kogyo Co LtdfiledCriticalNohmi Bosai Kogyo Co Ltd
Priority to KR7402960ApriorityCriticalpatent/KR790000175B1/en
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Publication of KR790000175B1publicationCriticalpatent/KR790000175B1/en
A gas detector, which detects specific gas selectively by temp. of a sensor, was composed of a sensor made from a metallic oxides semiconductor, sensor heating part and elec. resistance detection part of the sensor. The switching device alternately operates to raise and lower the temp. of sensor at periodic intervals. Gas is absorbed by the sensor at a low temp. an emitted at high temp. The resulted change in elec. resistance operates an alarm device.