This regulated power supply can be adjusted between a few volts and 15V with P1 and with P2 adjust the upper limit ( 15.0V ). R6 value is 0.7V / Imax where Imax is the maximum current. At Imax = 5A, R6 is 0.14Ω
T1 and T2 must have heatsinks because power losses are great at a low output voltage and a Imax equal current but you can connect the lamp L to reduce this losses.
I’ve build this adjustable power supply and works great! I hope you’ll enjoy it too and have fun build this great stabilized power supply.