How transistors amplify audio signals in megaphone circuit?

Microphone + Speaker = Megaphone
This is most simple definition of content inside this video. in this video you will learn how transistors amplify voltage and current and how to bias a transistor to do amaizing things for you.
This video will expand your analog vision.


Link to Current Amplifier Video
https://youtu.be/R4CO4pCBQuo

Link to CFL bulb video
https://youtu.be/9axYfWQQdno

Link to Microphone explanation video
https://youtu.be/hki_wkct1HM



also in this video you will get answers for these questions below.
What is easiest method to build a megaphone circuit?
How to connect a microphone to a speaker?
How to playback microphone sound through speaker?
How audio amplifiers work?
How a diaphragm works in microphone or speaker?
How much voltage can I apply to a speaker?
What does power and resistance mean in a speaker?
What is most simple audio amplifiers works?
How to shift voltage signal range using resistors?
How to bias a transistor using resistors?
Here in this video you will find answers of these questions