Guys, don't use a 680 Ohm resistor, instead, use a 3-4V Power Source, cuz only around 30% of total 12v energy (R*I^2) is being used there, rest is being wasted inform of heat due to resistance, to save from power loss use only 3-4v power source
why did you choose C1812 and D882 transistors rather than general purpose transistors. Please explain if there is any particular reason. Also give audio explanation in each video so that we do not do this project blindly.