Hello =) I am new to Electronics and i'm struggling with this exercise, I hope somebody can help~
http://tinypic.com/r/2j5c1l4/6
It reads: the Common Emitter has Voltage gain 20 without external load. a)Calculate the voltage gain when the common emitter leads to a 8Ω resistance speaker (left circuit)
b)Calculate the voltage gain with a common collector betwen the common emmiter and a speaker (right circuit)
Va=inf, b=100, I1=5mA
I tried the first one, and I came up with a 17,7 Voltage gain. If the CE has a Voltage Gain of 20=> uo/ui=20 <=> (-gm*ub*Rc)/(ib*uπ)=20 (1)
We want to calculate A'=uo/ui=(-gm*ub*(Rc//8))/(ib*uπ) (2)
(1)/(2) A'=17,7. I am not sure if it's correct so I would love some advice.
I'm stumped about the second part, mostly because I'm not sure what to do with the current source.
Thanks in advance for your time!
http://tinypic.com/r/2j5c1l4/6
It reads: the Common Emitter has Voltage gain 20 without external load. a)Calculate the voltage gain when the common emitter leads to a 8Ω resistance speaker (left circuit)
b)Calculate the voltage gain with a common collector betwen the common emmiter and a speaker (right circuit)
Va=inf, b=100, I1=5mA
I tried the first one, and I came up with a 17,7 Voltage gain. If the CE has a Voltage Gain of 20=> uo/ui=20 <=> (-gm*ub*Rc)/(ib*uπ)=20 (1)
We want to calculate A'=uo/ui=(-gm*ub*(Rc//8))/(ib*uπ) (2)
(1)/(2) A'=17,7. I am not sure if it's correct so I would love some advice.
I'm stumped about the second part, mostly because I'm not sure what to do with the current source.
Thanks in advance for your time!
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