Thus, a desired time varying pattern of {TAIL ~ energization} of {HEAD ~ the conductors} to accomplish a control function, e.g. the control of a central heating system to provide different heat outputs at different times of the day, can be set up at will simply by adjusting the various switches  
Thus , a desired time varying pattern of { TAIL ~ energization } of { HEAD ~ the conductors } to accomplish a control function , e.g. the control of a central heating system to provide different heat outputs at different times of the day , can be set up at will simply by adjusting the various switches
OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD 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 OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH