Product Description: In semiconductor testing, contactors can also be referred to as the specialized socket that connects the device under test. In process industries, a contactor is a vessel where two streams interact, for example, air and liquid. See Gas-liquid contactor. For other uses, see Contactor (disambiguation). AC contactor for pump application A contactor is an electrically controlled switch used for switching an electrical power circuit. A contactor is typically controlled by a circuit which has a much lower power level than the switched circuit, such as a 24-volt coil electromagnet controlling a 230-volt motor switch