{HEAD ~ The increasing number} of {TAIL ~ the power levels} is achieved by using electrical elements, such as resistors, transformers and others 
of
{ HEAD ~ The increasing number } of { TAIL ~ the power levels } is achieved by using electrical elements , such as resistors , transformers and others
HEAD 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