Proximity switch with logic and RC circuit - suppressing interference caused by alternating electromagnetic fields by introducing delay

摘要

The proximity switch has an oscillator coupled at its output to a flip-flop or trigger that operates an electronic switch, e.g. a thyristor or triac. The oscillator's output, or the output of the trigger is connected to its output, is passed to a logic circuit whose own output is coupled back to a first input and to a second input via an RC timing circuit at the oscillator's or trigger's output. The delay introduced by the RC circuit is at least half the period of any interference field and thereby allows alternating electromagnetic interference to be suppressed.