Greetings. It's been a minute since I've given an update. (I'm sure you've been waiting in bated breath too...)

(I talked about this project in these posts.) The original concept was from G. Randy Slone's book Electricity and Electronics from Tab Electronics. I used a combination of the book, the examples on the 317 data sheet, and a schematic from THE_RB. I also got invaluable assistance from #12, studiot, MrChips, ErnieM, and many others... Thanks so much.

So, while it's hardly perfect... my board layout is a joke, and the soldering hardly artful, I have a working unit now. Regulated 1.5-20V variable positive negative outs w/ground. Unregulated 36V positive and negative outs. It could perhaps use a kill switch, but I'm cool for now. It works great from what I can tell. The transformer is rated for 2A, but I have doubts I'd actually push it that hard.

Here's the view from the outside:

Inside:

Schematic (very messy!)

Thanks again for all your help here, and putting up with some pretty idiotic questions.. I couldn't have done it without you.

 

You need to refresh and tie the wires, and the wiring of the unregulated voltage side is not clear, could you redraw it?

 

Your current limiter is drawn so badly that I can't read it.
Be aware that a transformer can not deliver its rated current into a rectified output.
If you show your rectifier section we can tell you what the real limit is.
I suspect it is 1.29 amps.

 

There are many good free schematic drawing programs out there like DipTrace. Why not use them? An otherwise nice project looks really sloppy with a horribly drawn schmetic

 

@Blatboy

Nice work and good job for sticking with it until the end. The Slone book is not great and does not give all of the details so I am happy to see you got it done.

Here is the general schematic he was working from in the slone book he mentioned above. The OP added the protection diodes for driving inductive loads.

 

Yes! That's exactly what I used, to the letter, for the unregulated supply. The regulated supply was from the data sheet for the 317, which is certainly very similar to this here, and I added protection diodes as recommended by THE_RB in his schematic. I used a fancy "snap-in" panel LED for the power indicator. It was totally unnecessary to use this more expensive part, but it made it more fun. (Maybe I have a warped concept of "fun.")

I should have known better than to post that scribble on here. Haha. When I get some time. I'll clean it up and put it up either by hand or with a computing device (maybe I'll attempt doing it in Eagle as an exercise.)

ScottWang: You're right, I should tie down those wires. I'm not sure how much slack there is for me to do a real neat job, but I'll see what I can do.

This was fun. Many concepts were solidified. (And again, I appreciate all the nice answers to my sometimes not very smart questions...)

You can read all you want about electronics till kingdom come, but nothing replaces this kind of hands on experience.

 

Oh... and GopherT- The Sloan book doesn't spell everything out completely. I'm glad. It makes you do more on your own, so I wasn't just following a recipe. Of course, had I not had the internet (the oracle) and this forum as a resource, the project probably wouldn't have been finished, I'll admit.

 

DIY is really fun, I did a lots of diy.
You can visit my private web, I have had some diy inside, what you see was used google translation to translate from Chinese to English, the meaning may not appropriate, but the important thing is the circuit and results, some are diy from kits, the others was designed by myself.

Two 4 kinds ±5~15V fixed power.