User:Vijayalakshmi priyadarshni

type of amplifiers based on the input signal amplifiers 1.small signal amplifier 2.large signal amplifer “ based on the transister” a)common emiter amplifier b)common base amplifier c)common souce amplifier common amplifier                common amplifier is one of the three stage saingle bipolar junction transistor       input impedance                          zi=vi\ib                hfe=ic\ib→ ic=hfeib               applying kvl equations to the input side                    vi=ihie+ieRe                      =Ibhie+(Ib+Ic)Re                      =Ib(Hie+Re)+IcRe                      =Ib(hie+Re)+IcRe                      substitue ic= hfeib                      vi=ib(hie+Re)+hfeIbRe                 vi=Ib(hie+Re+hfRe vi=Ib(hie+Re(1+hfe)

the value of (1+hfe) is greater then hie