Flame and carbon monoxide sensor and alarm circuit

Claim 1

A gas Burner monitor comprising in combination: a source of electrical energy having a pair of terminals, a carbon monoxide detection circuit, a flame color sensing circuit, an alarm circuit, said carbon monoxide detection circuit comprising a gas detection element connected to said source of electrical energy and producing a first output signal when said detection circuit senses abnormal amounts of carbon monoxide around it, said gas detection element comprising a resistance means which changes its electrical resistance when subjected to the presence of carbon monoxide, said color sensing circuit comprising a phototransistor having an anode, cathode and base, said base being connected through a variable resistance to one terminal of said source and said cathode being connected directly to said one terminal of said source, said emitter being connected through a resistance to the other terminal of said source, whereby exposure of said photo-transistor to a predetermined level of light reduces the resistance of the phototransistor between said anode and said cathode to change the base to emitter current flow thereby producing a second output signal, said variable resistance biasing said phototransistor to render it sensitive to a desired light detection level, an alarm activating circuit, and means for connecting said first and second output signals to said alarm activating circuit to actuate an alarm.