How to build an audio amplifier using a single transistor?
Schematic:
https://drive.google.com/file/d/1Jsy7...
The transistor can be replaced with any similar NPN transistor. For PNP transistors, reverse the polarity. The capacitor is 0.22 - 1 uF, and the resistor is approximately 5 kOhm. This is a Class A amplifier, so the transistor gets quite hot, so for long-term use, it should be mounted on a heatsink.
I'll answer your questions in the comments.