Indeeco M & S Series power controllers are solid-state, zero-cross fired, proportional devices. Line voltage is switched 0-100% linearly, with respect to the input range. A 4 second time-base controls power to the load. For example, a 5VDC signal to a 0-10VDC input will cycle the output full on for 2.0 seconds and full off for 2.0 seconds. Line voltage is used to power the electronics. An external transformer is not required.