An integrator includes {TAIL ~ a source} of {HEAD ~ current} responsive to the signal to be integrated 
An integrator includes { TAIL ~ a source } of { HEAD ~ current } responsive to the signal to be integrated
OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH