When the alternating current is applied to the electromagnet as in the figure above the actuating rod moves first in the direction of the arrow as shown in Fig. A and then in the direction of the arrow as shown in Fig. B, by the magnetic attraction and repellent forces exerted between the electromagnet and the permanent magnets attached to the rod.

The rod vibrates at the same frequency as that of the power supply and changes the volume of the space enclosed between the casing and the diaphragm. Thus, the air intake, compression and exhaust can be performed through the valves.