Topic: Miller Theorem in Tuning Amplifier
We have a common emitter amplifier, with R, L and C connected between base and ground. Also R',L' and C' in connected between collector and ground. Cu and Cpi and Rpi are all considered. Now I want to find the input and output impedance considering Cu using miller effect.
I know that miller effect when impedance between two ports is only capacitance is reduced to:
Ceq = Cu * (1 - Vo/Vpi) (for base side)
Ceq = Cu * (1 - Vpi/Vo) (for collector side)

Now my question is that should I keep my Vpi/Vo as an imaginary number or abs(Vpi/Vo)?

Question

Topic: Miller Theorem in Tuning Amplifier
We have a common emitter amplifier, with R, L and C connected between base and ground. Also R',L' and C' in connected between collector and ground. Cu and Cpi and Rpi are all considered. Now I want to find the input and output impedance considering Cu using miller effect.
I know that miller effect when impedance between two ports is only capacitance is reduced to:
Ceq = Cu * (1 - Vo/Vpi)  (for base side)
Ceq = Cu * (1 - Vpi/Vo) (for collector side)

Now my question is that should I keep my Vpi/Vo as an imaginary number or abs(Vpi/Vo)?

anonymous · Answer

Ok, I found the answer in Sedra/Smith Microelectronics Circuits.