Again, switching may be accomplished through electro/mechanical devices such as relays or {HEAD ~ solid state devices} such as SCRs, {TAIL ~ triacs} or MOSFETS 
Again , switching may be accomplished through electro / mechanical devices such as relays or { HEAD ~ solid state devices } such as SCRs , { TAIL ~ triacs } or MOSFETS
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH