Semiconductor sensor for smoke, combustible gas and vapour detection

摘要

The semiconductor sensor is connected on one side to a variable source of stabilised voltage, and on the side to a variable source of constant current. The voltage source may be derived from any supply either of DC voltage or of rectified AC voltage. The variation of output from the sensor, in response to changes in concn. of smoke or vapour, may be measured either directly or after suitable processing. Voltage vs. concn. curves are presented for coal gas and natural methane, showing the range of adjustement of sensitivity in both instances.