Questions Regarding Electronics?

Question

Q no. 1) How does the BJT and MOS amplify? What is the main component responsible for amplification?

Q no. 2) What is the purpose of Coupling capacitors


Thank you

Answer 1

Transistor is the simplification of TRANSfer ResISTOR.The signals are transferred to a high resistance region.Hence the amplification of signals occur.The collector region is wide and have larger resistances than emitter and base.
2)Coupling capacitors are used in electronic circuits to couple two stages.It helps to prevent dc to go to the next stage which may interfere the stability.

Answer 2

Q #2) for passing AC signal, Blocking DC