Electronic proximity switch

摘要

This switch consists of two oscillators (O1 and O2) which oscillate at the same frequency and which are each followed by a counter (Z1 and Z2, respectively). The frequency of the first oscillator (O1) is changed by a first sensor (S1) when it approaches an object. The outputs of the counters (Z1 and Z2) are connected to a logic circuit which compares the frequencies of the oscillators (O1 and O2) determined by the counters. When the frequencies differ from one another, the logic circuit supplies an output signal. <IMAGE>