Each current control stage includes first, second, and third terminals, and means for conducting current between the first and second terminals in response to {HEAD ~ a control signal} present at {TAIL ~ the third terminal} 
present at
Each current control stage includes first , second , and third terminals , and means for conducting current between the first and second terminals in response to { HEAD ~ a control signal } present at { TAIL ~ the third terminal }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL