# Common base transistor with early effect

I have a circuit regarding common base transistor. I must find Av(Voltage gain) Rin(input resistance) Rout(output resistance). Our teacher said you should analyze CE + RE + RS transistör circuit. And I have drawn figure 1, figure 1 is below

Also I tried to solve this problem by using source changing. I have drawn it like below

I have 10 circuit and one of them is CE + RE. I could solve it but unfortunately I couldn't solve including CE + RE + RS one. Do you have any trick point for me ? How can I solve this question ?

Thank you so much.

• First identify why you can't solve it. Then do some research on whatever aspect of the circuit you identified in step 1. If that research doesn't allow you to solve the question, edit this question to ask something more specific. Nov 8, 2020 at 13:39
• Take a look at this example electronics.stackexchange.com/questions/380184/…
– G36
Nov 8, 2020 at 14:13
• @BrianDrummond Thanks for your suggestion. I can't solve this question because of RS. I am trying to find an equation between Vout and Vin by looping emitter and collector but I couldn't find voltage of RE.
– Piko
Nov 8, 2020 at 14:14
• @G36 Thank you, I will look at your example.
– Piko
Nov 8, 2020 at 14:17
• Also for Rin take a look at this as well electronics.stackexchange.com/questions/429716/…
– G36
Nov 8, 2020 at 14:22