A voltage stimulus applied to the drain forces current to flow through {HEAD ~ the channel} coupling the drain to {TAIL ~ the source} 
A voltage stimulus applied to the drain forces current to flow through { HEAD ~ the channel } coupling the drain to { TAIL ~ the source }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL