The control provides quick response and actuates {HEAD ~ the level control} to effect {TAIL ~ accurate maintenance} of the required liquid level in an air pressure control system or, for example, a variable resistance control in an electrical control system 
to effect
The control provides quick response and actuates { HEAD ~ the level control } to effect { TAIL ~ accurate maintenance } of the required liquid level in an air pressure control system or , for example , a variable resistance control in an electrical control system
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL 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