Study of Hot-wire Detecting Instrument

A temperature detect scheme of hot-wire method with electronic switching is given in this paper. The change of heating state and sensing state for thermocouple is completed successfully. The comparator controlling circuit and detecting circuit are analyzed. The inline error decreases with linear alignment circuit. A mesentery system composed of an 8031 single-chip is established. The methods which stabilize the switching voltage are used in order to increase the measurement accuracy. Besides, sample hold circuit and digital display circuit are used in the scheme. The feasibility of the detecting instrument is also proved with experiments.