{HEAD ~ Small perturbations} in {TAIL ~ the drive voltage} are applied at a level to cause a measurable variation in the sensor output current 
in
{ HEAD ~ Small perturbations } in { TAIL ~ the drive voltage } are applied at a level to cause a measurable variation in the sensor output current
HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH