ok, i am starting to get it, but could anyone please explain "Vdz(1+(R3+R4)/R5)". what is Vdz??
and yes the collector of T1 is connected to ground via the capacitor and to the positive of input as well via D1( what is the function of D18-O:?: ). But if it has to work as emitter follower, why is it grounded?
and what is 1.5V? where did it come from?
and what should i do to make this power supply a variable one? like if i supply full 15V, i want it to go from 0 to 12.5v. will any variations be required at pin 3 of 741?