How does a transistor amplify an AC signal (when it works on DC and cannot change current direction)? - Quora
![Why is DC component ignored and AC analysis is used when obtaining input output impedance of a BJT transistor amplifier? - Electrical Engineering Stack Exchange Why is DC component ignored and AC analysis is used when obtaining input output impedance of a BJT transistor amplifier? - Electrical Engineering Stack Exchange](https://i.stack.imgur.com/jNqFD.png)
Why is DC component ignored and AC analysis is used when obtaining input output impedance of a BJT transistor amplifier? - Electrical Engineering Stack Exchange
![Amazon.com: Todiys New 40Pairs for 40Pcs B647 B647A B647-AC 2SB647A + 40Pcs D667 D667A D667-AC 2SD667A to-92L Silicon PNP Transistors 2SB647AC + 2SD667AC : Electronics Amazon.com: Todiys New 40Pairs for 40Pcs B647 B647A B647-AC 2SB647A + 40Pcs D667 D667A D667-AC 2SD667A to-92L Silicon PNP Transistors 2SB647AC + 2SD667AC : Electronics](https://m.media-amazon.com/images/W/IMAGERENDERING_521856-T1/images/I/51kF9bF-qyL._AC_UF1000,1000_QL80_.jpg)