Ai=Av*hfeA1=Ai*Rc/RbSolving Amplifier Questions with Low Frequencies

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SUMMARY

The discussion focuses on solving amplifier questions related to low frequencies using a transistor with specified h parameters: hie = 1.1 kΩ and hfe = 50. The user seeks assistance in calculating parameters such as A1, Ais, Av, Avs, Ri, Ri', R0, and R0' based on a pi model representation. Key equations discussed include Av = V0/Vi and Avs = [Ri/(Ri+Rs)]*Av, emphasizing the importance of correctly placing Rb in the pi equivalent model and computing Rpi for accurate results.

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  • Understanding of transistor h parameters (hie, hfe)
  • Knowledge of amplifier circuit analysis
  • Familiarity with pi model representation of transistors
  • Basic skills in calculating voltage gain and input/output resistances
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Electrical engineering students, circuit designers, and anyone involved in amplifier design and analysis, particularly in low-frequency applications.

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Homework Statement



We have an amplificator of low frequences like in the figure.The transistor has these h parameters:
hie=1.1k Ohm,hfe=50 Ohm
In the entrance we have Vs and Rs=10 kOhm.
Find A1,Ais,Av,Avs,Ri,Ri',R0 and R0'


Homework Equations



There are many.

The Attempt at a Solution


I ,myself did the pi model like in the figure.Is it correct?
Please,check if I have put Rb in the right place in the pi equivalent
http://i.imgur.com/ClGTLdd.jpg

ALSO,can you please help me find what is asked?
I think that
V0=i0*Rc=-gm*vpi*Rc
Vi=ib*(Rb|| rpi)=Vpi*(Rb/(Rb+rpi)
Av=V0/Vi
Avs=[Ri/(Ri+Rs)]*Av
 
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hfe is dimensionless. Your value of 50 looks too low anyway.

Your model looks OK. Did you compute Rpi?

You are nasking for a lot of parameters and need to define each of them for us.