Photoelectric switch.

摘要

A photoelectric switch, comprising: a heating unit (24) formed around a beam transmission part (23) of a light transmitting plate (22) provided on a body (21) having a light receiving part; a received light quantity decision circuit (27) for generating an electrical signal corresponding to a quantity of light received on said light receiving part (28), comparing the electrical signal with a set level to decide whether or not it is on the set level or below; a temperature circuit (25) for generating an electrical signal corresponding to a change in ambient temperature of said body (21); a driving circuit for actuating said heating unit (24) to heat on condition that the electrical signal of the temperature circuit (25) has reached a level of set temperature or below, and that said quantity of received light has come to the set level or below.