Pressure detecting apparatus

摘要

A pressure operated detecting apparatus for providing highly sensitive on-off and distance measuring signals. The apparatus comprises an air bridge circuit which includes a semiconductor chip utilizing the piezo-resistance effect. The chip is exposed at opposite sides to a reference air pressure and a subject air pressure which is variable in response to an approaching object. The chip produces an output voltage in response to the difference in pressure which is amplified and converted to an analog signal which is usable for distance measuring. The analog signal is also compared to a reference voltage in a comparator which generates an on-off binary signal.