Patent ID: 6489787
Filing Date: 2002-12-03
Classification: G01N

Abstract:
A natural gas detection circuit comprised of:a first Wheatstone bridge circuit comprised of: an active element; a reference element, said active element and said reference element aligned in series on a first half of said first Wheatstone bridge circuit; a first fixed resistor; and a second fixed resistor, the first fixed resistor and the second fixed resistor aligned in series on a second half of said first Wheatstone bridge circuit, said first half of said first Wheatstone bridge circuit being aligned in parallel with said second half of said first Wheatstone bridge circuit; and a second Wheatstone bridge circuit comprised of: said active element; said reference element; a third fixed resistor, said active element, said reference element, and said third fixed resistor aligned in series on a first half of said second Wheatstone bridge circuit; a fourth fixed resistor; a fifth fixed resistor, said fourth fixed resistor and said fifth fixed resistor aligned in series on a second half of said second Wheatstone bridge circuit, said first half of said second Wheatstone bridge circuit being aligned in parallel with said second half of said second Wheatstone bridge circuit; and a fixed voltage regulator, which provides power to said gas detection circuit, the fixed voltage regulator maintaining a fixed voltage difference across said first Wheatstone bridge circuit and said second Wheatstone bridge circuit.