摘要：

A gas sensor for detecting a gas component from a food item includes a sensing layer having an electrical resistance value that varies in accordance with the concentration and type of the gas component generated from the food item to thereby sense the gas component, first and second electrodes coupled across the sensing layer and connected to a power supply, a heater for heating the gas sensor to a temperature of sensing operation, and a switch connected to an adjustable voltage supply for controlling whether the heater is operated in a first temperature range or in a second temperature range. The sensing layer includes a mixture of SnO.sub.2 and WO.sub.3 in a predetermined ratio.

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