Abstract: The present invention provides a controller for an air compressor system. The air compressor system includes an air compressor, control unloaders on the air compressor to prevent the air compressor from compressing gases when signaled to unload, an electric motor for driving the air compressor, and a tank for receiving and storing compressed gases from the air compressor. The controller has an adjustable pressure switch to raise or lower the discharge pressure. The differential pressure is pre-set in the pressure switch. The controller includes two methods of operating the air compressor, each of which is manually selected by operating a switch that will designate start/stop control or automatic dual control at the option of the operator. The start/stop control will start the motor when the pressure in the system reaches a predetermined low point. When the preselected high pressure point is reached, a signal is sent to the motor to stop, thereby ending the compressing cycle.