Automatic transfer switch systems and controllers

An automatic transfer switch (ATS) controller is disclosed which includes a power supply circuit to regulate and filter input power, a transformer to convert utility and generator power sources into power supply voltages and voltage sensing sources and a voltage sense signal conditioning circuit. Controller further implements a solenoid driver circuit to drive automatic transfer switch solenoids, an embedded microcontroller configured to monitor utility and generator voltages and a user interface interfaced to said microcontroller for operator entry of instructions. A LED indicator is included and is configured to verify user interface entries and overall operation of the controller and ATS system.