These Sensors are designed to work as solid state DC limit switches. The Sensors are connected directly in series with the load and have a bridge rectifier so they are not polarity conscious. The circuit design is such that, when in off state, it allows very low current to flow through the load. However, the output load (such as relay) should be chosen, considering the voltage drop across the switch in the ON State. These sensors find wide application in electric control circuits and PLC’s.