This device consists of a Hall Effect semiconductor sensor separated across a small gap by a magnet. In its normal state the Hall sensor (with inbuilt output transistor) is conducting. It will sink up to 40mA between the impressive temperature range of -40 to +150 degrees C. When an iron vane is introduced into the gap between the Hall element and the magnet, the output transistor switches off. The sensor is hermetically sealed, resistant to petroleum products and incorporates metal bushed mounting hols to facilitate fitting to a carrier plate, bracket etc. It is ideal as the commutator for an electronic ignition; however it has many other usage areas. Lead connections: Red V+, Black earth, Green signal (on/off).