in a few regulated power suplies that i've seen it appears that NPNs are used for voltage regulation while PNPs are used for current regulation. is this right?
What eactly is the diffrence (in terms of application) between these two transistor types
now that is saying alot in few words. but can you know tell me how these transistors work together to give both a variable voltage and variable current source?
P2 adjusts the voltage and P1 adjusts the current.
The circuit doesn't have a proper voltage reference (like a zener diode) so its voltage regulation won't be very good.