{TAIL ~ The preconcentrator} may also include {HEAD ~ a resistor} and a proportional integral differential controller 
{ TAIL ~ The preconcentrator } may also include { HEAD ~ a resistor } and a proportional integral differential controller
TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH