7.7fortheclassBamplifierofFigureofProblem7.2,calculate:a.MaximumPo(ac).b.MaximumPi(dc).c.Maximumη%.d.Maximumpowerdissipatedbybothtransistors.+Ucc(+30V)R1C1VT2uLuiRLVT1ΩR34C2R2-UEE(-30V)FigureforProblem7.2Solutions:222UCC230V(a)maxPi(dc)71.63WRL822UCC30V(b)maxPo(ac)56.25W2RL28P()ac56.25W(c)%o100%100%78.5%Pi(dc)71.63W222UCC230V(d)maxPW2Q2222.8RL87.8iftheinputvoltagetothepoweramplifierofFigureofProblem7.2is8Vrms,calculate:a.Pi(dc).b.Po(ac).c.η%.d.Powerdissipatedbybothtransistors.Solutions:Ideally,thepoweramplifierhasavoltagegainofunity,thepeakinputandoutputvoltageisVL()pVi()p2ui28V11.3VThepeakloadcurrentisVpL()11.3VIL(p)1.4125ARL8Thedccurrentfromthesuppliesis22II(p)1.4125A0.899AdcL(a)ThepowersuppliestothecircuitisPi(dc)UCCIdc(30V)(0.899A)27W(b)Theoutputacrosstheloadis22UL11.3VPo(ac)8W2RL28(c)ThepowerdissipatedbyeachoutputtransistorisPPPWW2Qio27819(d)ThecircuitefficiencyisP()ac8W%o100%100%29.6%Pi(dc)27W