Correct Hybrid Pi model?

[fouadalnoor]

Hey guys, in trying to answer this question, did I draw the correct Hybrid Pi equivalent circuit? (look at attached images)

 

[mgr1397]

No,
That capacitor in the Emitter acts like a short when you put an AC signal therefore there shouldn't be a resistor at the emitter (Re) when you draw the Hybrid pi model.

Otherwise everything looks good

 

[fouadalnoor]

No,
That capacitor in the Emitter acts like a short when you put an AC signal therefore there shouldn't be a resistor at the emitter (Re) when you draw the Hybrid pi model.

Otherwise everything looks good

Ah, but in the question it says Ce cannot be neglected while Cc can be considered a short circuit

 

[Winterstone]

Hey guys, in trying to answer this question, did I draw the correct Hybrid Pi equivalent circuit? (look at attached images)

I must confess, it is not very easy to read your drawing - nevertheless, I incline to see an error: The diagram does not consider the fact that the input impedance is increased by Ze*(1+hfe).
That means: The feedback effect is not included.
Thus. remove the lower part (parallel combination) amd replace the input resistor rfe by the expression [rfe+Ze*(1+hfe)].
With Ze=emitter impedance (R||Xc) and hfe=forward current gain.