{TAIL ~ One switching circuit} is {HEAD ~ an electrical switching circuit} and the other is an electromechanical switching circuit 
{ TAIL ~ One switching circuit } is { HEAD ~ an electrical switching circuit } and the other is an electromechanical switching circuit
TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH