초록 ▼

A gas sensing instrument provides programmable control of the operating temperatures of an array of gas sensors for the detection of target gases in air. The control facilitates precise temperature setpoint resolution. The gas sensors in the array have an improved construction density with reduction

A gas sensing instrument provides programmable control of the operating temperatures of an array of gas sensors for the detection of target gases in air. The control facilitates precise temperature setpoint resolution. The gas sensors in the array have an improved construction density with reduction in size and an extended operating life provided by reduced power consumption. A programmable circuit functions as a programmable-resistor temperature controller in a Wheatstone bridge configuration. A multiplying digital to analog converter circuit controls the ratio of voltage to current that functions as a resistance equivalent. The programmable circuit is interfaced with a computer to provide selectable temperature control for at least 256 setpoints.

대표청구항 ▼

An instrument for simultaneously quantifying the concentrations of a number of gases present in an oxygen containing atmosphere comprising, a computer for providing a quantitative presentation of the gas concentrations, a number of semiconductor gas sensing elements at least equal in number to the n

An instrument for simultaneously quantifying the concentrations of a number of gases present in an oxygen containing atmosphere comprising, a computer for providing a quantitative presentation of the gas concentrations, a number of semiconductor gas sensing elements at least equal in number to the number of gases to be detected, said gas sensing elements each having a predetermined quantifiable response characteristic differing from the response characteristic of the other of said gas sensing elements in response to at least one of the gases to be detected, temperature control means for maintaining the temperature of each gas sensing element at a selected value by compensating for thermal variations in the surrounding environment, said temperature control means coupled to and responsive to said computer to maintain each of said gas sensing elements at a selected one of a number of operating temperatures, measurement means connected to each of said gas sensing elements for generating an electrical signal representing the response of each of said respective gas sensing elements to each of the gases to be detected, said measurement means electrically connected to said computer, and said computer including means for converting said electrical signals from said measurement means to a digital representation,