Working of components in Common Emitter Amplifier Circuit.

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Shayaan_Mustafa

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Hello experts!

I have some questions. Here is my schematic.

1) What do coupling capacitors do in common emitter amplifier and why they are used? And what would happen with ouput if they were not there where they should be?

2) What does Emitter resistor do and why it is used? What will be the output response if RE is not there?

3) What does bypass Capacitor do across RE? What will be the output response if CE is not there?

Answer#1) Coupling capacitor is to separate DC from AC. If it is not there then output will be shifted from its reference. For example, with coupling capacitor output is \[\pm\]5V(swing i.e. 10VCC) and without capacitor output will be shifted let it is 1V so the output we will get as +6V and -4V(as DC has been added to the output without coupling capacitor)

Answer#2) It is a feedback, a negative feedback. But don't know why it is used?

Answer#3) It passes high frequencies so as to ground them easily and provide high gain in contrast to there is no bypass capacitor. But what about for low frequencies?

Thanks.
 

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Thanks for reply.
But I don't want to refer it. Because if I have to do it then why I post this problem on www.edaboard.com
I want to discuss this topic here with experts.
Thanks.

Mustafa, I can understand your desire.
However, I think such a forum like this is really not the right place to present and discuss fundamentals of circuit design - in particular the important aspects of feedback.
Do you know that there are books (300..400 pages) devoted to feedback systems only?
In your case, perhaps some basic papers on feedback (principles, pros/cons) available to download are sufficient.
regards
 
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