pigster

HURRAY, last problem solved, i have just changed connection of Q1 emitor and all is OK. First part of project completed (second one is adding a digital meter, but that will be another story). Thanks to all who helped me, i will post some photos soon.

I use TIP31A, and i have its emmitor connected directly to (-) output of supply, as you suggested earlier in this forum. But thanks, i will repleace Q1 and we will see. Thanks

so at last i had time to inspect my supply further, and have little bit more info about turn-off peek, i have repleaced C1 (dont know if it was defective or not, i have just repleaced it, now it is 10 000 uF / 63V) , but i have also discovered, that if the voltage regulator is set to 4,5V or less, than i turn off the mains, and than i have about 36V on output (so C1 discharges into load on 36V), but if the voltage regulator is set higher than 4,5V (for example 5V), than all goes right and after turn-off i have 5V on output as C1 discharges. This was measured without load (just voltmeter connected to output). Any ideas? And how does the voltage regulator works, if there is no negativ voltage (mains off, but C1 still charged)?

Thanks for explaining negative circuit, about the peek problem, i have checked all components in negative part, all is ok including 82 ohms R2. I have also done little experiment, i have connected LED to output of PSU, set voltage to about 1,8V, all is fine, LED is ligting, then i have switched off the mains switch and .... amusing efect happened as LED burned out. Any ideas?

Hi everyone, i have just finished this supply, i have used all modifications mentioned in this forum except change of opamps. Btw, doubled 2N3055 is REALLY good idea. All is working fine, i have only one problem and don't know if it is problem in construction or in design. If i turn the PSU on, there is huge voltage peek. For a moment the transformer output voltage appears on output (my is 28V). If i turn the PSU off, than i have about 35V on output and is falling down (as C1 discharges). When the PSU is turned on, it operates normally. Oh and R2 gets sometimes little bit hot (maybe someone can explain me why the combintion of R2 C2 is here, and connected directly to transformer output) Thanks fo replies (sorry for my English)