Combustible gases detection circuit - has several channels each with a pickup sensitive to combustible gas-air mixture

摘要

The detector includes pickups which change their resistance when exposed to a combustible mixture, and are supplied with constant current, with bridge circuits between pickups and their current sources. Signal processing elements connected with the bridge output for its output signals adjustment. A channel selection unit is connected to the channel outputs and selects the channel with highest signal output. A display unit displays the detected gas concentration, with means controlling an external signal. Failure detecting units connected to the above current sources deliver an output signal when a current source fails. This unit output is connected to the channel selection unit, so that it delivers an output signal to channel selection means so long as any of the channel delivers a signal.