My goal was to amplify audio signal coming from Raspberry PI's audio jack, so it is louder. I have basically no clue what I am doing, but it seems to work - when I connect the speaker directly to the audio jack, it is very weak, but connecting with transistor makes much louder sound.
Is my circuit correct?
Or am I going to destroy the speaker or even raspi?
How comes there is no GROUND needed in my circuit?
My transistor is CTBC 640 My speaker is 8 ohm, 0.25W