As a project for my electronics 101 class, I've been assigned to design a three stage amplifier using bjt transistor to achieve a gain of 150 and input resistance of 100k and output resistance of 50 ohms .I have tried to do so, but the result is less than satisfactory, I really need the help of an expert.(The question might sound basic to you,so sorry that I'm a beginner.)
I know for a fact that this circuit has many flaws. First of all the output resistance is not 50,It's 90. Secondly,The 200k resistance that I've used at the beginning of the circuit to make the high input resistance,dampens the signal,so in a sense, my circuit dampens the signal at first and then amplifies it. Thirdly, my dc sources are too many, I can make use of only one dc source,so this last problem is not really something that I worry about.And my gain is something about 105 which is not satisfactory.
1.I would really appreciate it if you help me on this.I think I should use a Common Collector stage as the last stage,but I have trouble configuring/understanding the output resistance of a common collector stage.
- I have no idea how I should make the input resistance as high as 100k without dampening my signal.
3.Do you think the correct configuration to achieve gain of 150 is CE-CE-CC?
As I've said before,I would really appreciate your help.I'm pretty much clueless on how to even begin improving my design to match the specifics of the assignment.So any help, big or small is needed.