The magnetization of the cylinder electromagnet generates magnetically attracting force between the cylinder and the piston to cause the piston to move in a one direction and {HEAD ~ thereafter magnetically repellent force} to transfer the piston in {TAIL ~ the opposite direction} 
The magnetization of the cylinder electromagnet generates magnetically attracting force between the cylinder and the piston to cause the piston to move in a one direction and { HEAD ~ thereafter magnetically repellent force } to transfer the piston in { TAIL ~ the opposite direction }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL