Abstract: A control panel, formed entirely of solid state components, for an automatic transfer switch which alternatively connects a load to a normal source of power or starts up an emergency source of power and connects the load to it. The control panel includes monitors for the normal and emergency sources, the monitors having a pickup voltage and a lower dropout voltage, relays for initiating operation of the emergency or normal sources when the normal source drops below the dropout level or the emergency source rises above the pickup voltage or frequency level, and time delay circuits between the monitors and the relays preventing operation of the relays unless the voltage levels exist beyond the time periods provided.