The switching circuits are chosen such that {HEAD ~ defects} causing {TAIL ~ the electrical switching circuit} to short circuit do not affect the electromechanical switching circuit and defects causing the electromechanical switching circuit to short circuit do not affect the electrical switching circuit 
The switching circuits are chosen such that { HEAD ~ defects } causing { TAIL ~ the electrical switching circuit } to short circuit do not affect the electromechanical switching circuit and defects causing the electromechanical switching circuit to short circuit do not affect the electrical switching circuit
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL 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