{HEAD ~ A length difference ld} between {TAIL ~ the core length lm} and the coil length lc is preferably equal to or greater than the former thickness tf 
{ HEAD ~ A length difference ld } between { TAIL ~ the core length lm } and the coil length lc is preferably equal to or greater than the former thickness tf
HEAD HEAD HEAD 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