β=210, Vt=26mV, Vbe(on)=0.7V
How to find Vs,
then find the Voltage gain Vo/Vs ?
I try to draw the small signal model to solve the problem
Vth=15*R2/[R1+R2]
Vth=1.62V
Rth=R1//R2
=5.5kΩ
Vth+Rth*Ib+Ie*Re+Vbe=0
Vth=Rth*Ib*(1+β)*Re
Ib=(VthVbe)/Rth+Re(1+β)
=8.2μA
Since
Re is short in Ac
Rπ=Vt/Ib
=3.18k ohm
Vo=β*ib*Rc
How to find Vs,
then I can get Vo/Vs ?
How to find Vs,
then find the Voltage gain Vo/Vs ?
I try to draw the small signal model to solve the problem
Vth=15*R2/[R1+R2]
Vth=1.62V
Rth=R1//R2
=5.5kΩ
Vth+Rth*Ib+Ie*Re+Vbe=0
Vth=Rth*Ib*(1+β)*Re
Ib=(VthVbe)/Rth+Re(1+β)
=8.2μA
Since
Re is short in Ac
Rπ=Vt/Ib
=3.18k ohm
Vo=β*ib*Rc
How to find Vs,
then I can get Vo/Vs ?
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