Understanding the Physics Behind Common Emitter Transistors

[Garoll]

Hello,

I would like to ask someone to explain me the basic physics of the common emitter configuration.
With the common base configuration i am understanding all the processes with holes and electrons in the npn transistor perfectly.
In the common emitter configuration i can`t understand why the collector current is increasing when we increase the base current. My logic leads me to the fact that when the base current is increased there should be more recombination in the base with electrons from the emitter and the collector current should decrease, but it is exactly the opposite.

I would appreciate if someone could help me with this issue.

Regards

 

[digitalblggr]

I looked through this article, and the explanation is pretty good:

http://en.wikipedia.org/wiki/Common_emitter

otherwise you can get hold of this book:

https://www.amazon.com/dp/0521370957/?tag=pfamazon01-20


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[jsgruszynski]

Absolutely nothing actually changes in terms of bias (all common-X are linear bias) or physical operation of the BJT itself.

The big difference in the resultant terminal-to-terminal gain and impedance seen that result from the *topological* difference of connections.