The comparator circuit controls {TAIL ~ the lighting} of a go/no {HEAD ~ go indicator LED}, which tells the operator which side of the readhead is more sensitive to the magnetic flux 
The comparator circuit controls { TAIL ~ the lighting } of a go / no { HEAD ~ go indicator LED } , which tells the operator which side of the readhead is more sensitive to the magnetic flux
OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH