It should be understood that positive and negative are relative terms in {HEAD ~ reference} to bias voltage applied to a source of an N channel or {TAIL ~ P channel device} 
It should be understood that positive and negative are relative terms in { HEAD ~ reference } to bias voltage applied to a source of an N channel or { TAIL ~ P channel device }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL