An amplifying circuit amplifies and outputs {HEAD ~ voltage difference} between {TAIL ~ first external input voltage} and voltage corresponding to second external input voltage 
between
An amplifying circuit amplifies and outputs { HEAD ~ voltage difference } between { TAIL ~ first external input voltage } and voltage corresponding to second external input voltage
OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH