Thus, during a portion, Δ, of each period P, there is {TAIL ~ a dead zone} during which {HEAD ~ both transistors} Q1 and Q2 are in non conducting condition 
Thus , during a portion , Δ , of each period P , there is { TAIL ~ a dead zone } during which { HEAD ~ both transistors } Q1 and Q2 are in non conducting condition
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL REL OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH