A proximity switch with a noncontact effect which includes a plug-in adapter having a plug-in socket for the sensor part equipped with a plug-in cable, a ac/dc converter with a core coil connected in front thereof being arranged in the adapter. The adapter is associated with a dc/ac converter located...http://www.google.es/patents/US4864156?utm_source=gb-gplus-sharePatente US4864156 - Proximity switch with noncontact effect
