# Peak gain and IP3 of a common-emitter amplifier

1. Jul 31, 2015

### DavidEE

1. The problem statement, all variables and given/known data

2. Relevant equations
Hi all.
Lets start with subquestion a).
How do i calculate the PEAK gain?

3. The attempt at a solution
I drew the small signal equivalent and calculated the gain: Av=vo/vi=-gm(ro//R=1kΩ//L//C)
Is that correct? How do i now calculate the peak gain?

Thank you for you help!

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2. Jul 31, 2015

### SeanS6

It seems like the best bet would be to look in a basic electronics book. Like for example your course book. You kinda like read the thing, follow through some of the worked examples. Sometimes you get stuck and you have to reread a section a few times or check something on the internet. You are wasting your own time if you really believe you can get through a technical course without reading anything. It would be better to enter the workforce straight away if you can't/won't do the basics. Flip the burgers or read the books. 18+ you're an adult. Mom and pop can't buy you a great job.

3. Jul 31, 2015

### DavidEE

Wow, that was helpful, thanks!

4. Jul 31, 2015

### LvW

David - do you really mean R||L||C ? Which dimension do you expect as a result?
Have you heard already about the term "resonance"?

5. Jul 31, 2015

### DavidEE

I mean R||sL||1/sC.
r0 can be neglected.
That would result in jwRL/(R-w^2RCL+jwL).
The peak gain would be at w=1/sqrt(LC)? (Thanks LvW)
After some calculations i get Av=-gmR=-(Ic/Vt)R= -38.4, IAvI=31.7dB

6. Aug 1, 2015

### LvW

Yes - the result looks OK (for case a).

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