adamjclark
New Member
hello all, This is my first post here. I am pretty new to electronics and I have a very basic understanding. I am building my own psu. Heres what I want. I would like to have a 1.5-30vdc 5a dual supply with adjustable voltage and current. I want to use as much stuff for it as I can that I already have. I made a schematic that uses 4 lm317's with pass transistors and an lm308 for the voltage regulator circuit. My transformer has 3 sec. coils. the HV sec. with center tap is 44.5vac, the other 2 doesn't have center taps and one is 38.5vac and 8vac. Im using a mb354-w bridge rectifier that is 40-100v at 35a. after the rectifier the HV sec is 62vdc. this is where the problem starts. the max input for the 317's is 30vdc and the 308 is 18vdc. I need to step down the voltage from 62 to 30 without limiting the current. I have a few other issues but this is the first and most important one I need to get past before I can move on. Thanks