I'm going to design amplifier, requirement is that input impedance should be more than 20kohm, output impedance should be less than 50ohm, and voltage gain should be more than 200. So I'll make cc-ce-cc amplifier, but how can I choose transistor for each cc, ce, cc? And is it better to chooose transistor first and after that choose Rc, Re...and then R1, R2...etc? Or is there any other better way(order) to design it? Any guide will be appreciated. Thanks

 

You have chosen the wrong amplifier structure. I prefer to make the amplifier with a large gain and reduce the gain using negative feedback. This will increase the stability of the gain and reduce distortion. What you are proposing is a school approach. Well, try it. But you have to consider that there can be a more serious approach. See:

 

@Bordodynov
I just tested the asc file, but the left side of the graph table labeling as 0dB~20dB, they didn't like yours shown the voltage as 0V~360V.

 

I just tested the asc file, but the left side of the graph table labeling as 0dB~20dB, they didn't like yours shown the voltage as 0V~360V.

Move the mouse cursor at the Y-axis (the cursor turns into a ruler). Now, right mouse click to enter the menu and change the axis from Decibel to Linear.

 

Move the mouse cursor at the Y-axis (the cursor turns into a ruler). Now, right mouse click to enter the menu and change the axis from Decibel to Linear.

Thank you.
I just want to try the original conditions as the posted graph table.

 

See

 

An opamp will be better I think. You will have a high current gain on the output. Why not use an OPAMP with a transistor on the output?

 

And what will you do if the signal source is very low impedance. In this case, of course, you can use an operational amplifier, but the goal is not this particular amplifier, but learning to build circuits. I push the idea that the amplifier electronics is not just a set of simple cascades, but an art. And that from the same number of transistors, using imagination and skill, you can extract more. Unfortunately this is not taught in school. It is also possible to vary the amplifiers using transistors of different conductivity and different types.

 

Here is a more perfect scheme. It has more input resistance, less noise and a small output resistance.

 

See CE-CC-CE:

 

, but the goal is not this particular amplifier, but learning to build circuits. I push the idea that the amplifier electronics is not just a set of simple cascades, but an art. And that from the same number of transistors, using imagination and skill, you can extract more. Unfortunately this is not taught in school. It is also possible to vary the amplifiers using transistors of different conductivity and different types.

Excellent reply, every thing you said is right on. Thank you.