This is my first real project in electronics! I started by looking at the schematic and scratching my head a lot then just went for it!

I put the bits and bobs on the board and soldered them into place, wasn't really sure how or where to put the bits. Then i started soldering the wires as in the schematic that's easier said than done! after a few hours things started to come together, i finished the board and tested and to my amazement the psu worked! i would like to show afew pics and the schematic i used.
<p>Hi </p><p>I have a problem,after giving all the connections as per the diagram,the output voltage has only a minor difference(+/-2-6) even is the variable resistor is adjusted.</p><p>Any idea what may be the problem?</p>
<strong><em>VERY NICE JOB!</em></strong><p>I notice on the schematic your note &quot; <u>DO NOT</u> <strong>CONNECT THE GROUND OF THE AC POWER TO THE COMMON OF THE POWER SUPPLY</strong>&quot; .</p><p>Looking at the photos I do not see that ground wire at all.</p><p>I would <strong>connect the AC ground to the case of the power transformer, so that if the transformer should ever short out internally you would not have a hot transformer when servicing.</strong></p><p>Also I do not see the <strong>0.5A </strong> fuse shown in the schematic mounted anywhere, this I would always recommend be mounted to a externally (See Photo) accessible fuse holder with the center connector connected to AC HOT and side connector to transformer.</p><p>That way you cannot come in contact with the <strong>HOT AC while changing the fuse.</strong></p>
<p>I made mine in a velleman kit box, also it has a fixed 5v output provided by a 7805, along <br>with a variable voltage output from lm317. the battery seen is powering the voltmeter. <br>it is controlled by relay so it powers on with the power supply and <br>shuts off with the power supply. voltage range depends on wall adapter. <br>current range is 1.27V DC to 16VDC. i prefer clear case so i can see inside.</p>
Sorry, just to be clear, can you just replace the Lm317 with and Lm350 with out changing anything else or would it change the range or voltages or anything? Thanks :)
Can I use a 24v transformer without changing scheme ?
Now i'd rather use Lm350. <br>Cause it gives max 3 Amps. <br>LM317 has max of 1.5 Amps. <br>And yes you can use 24V with no problems. <br>Just make sure you use a cooler.
You look like you're off to a great start to me. Even if you're just building a circuit on perfboard I find it helps to model the circuit first in board design software. It makes the final build go a lot easier, and come out better for me too. Easier to play around on the computer, than with a soldering iron. <br> <br>Your first supply came out a lot better than my first one did. When I made mine there weren't any personal computers though, so I guess I get a little slack there.
Actually for something like a drill ,you don't need a regulator. If you use a 12v transformer all you have to do is rectify it with a bridge &amp; add a capacitor to smooth it a bit &amp; it will be happy. Drills under load take a lot of current , probably in the 10-15 A range. A good place to get high current transformers cheap is to get an old UPS, used for computer backup power &amp; remove the step-up transformer. Wire it so the output side is now the primary &amp; you have a great low voltage source. Usually they are within a couple of volts of what the battery voltage of the UPS was. i.e. 12v battery = 11v to14v ac . Current is roughly wattage of UPS / battery voltage. 300W/12v = 25A I have a bunch of these beasts around home &amp; work , great for brute force power.. <br> <br> <br> <br> <br> <br> <br> <br> <br> <br> <br> <br> <br> <br> <br> <br> <br> <br> <br> <br> <br> <br> <br> <br> <br> <br> <br>
Thank you for the info i should have thought of that myself! i have in the past cracked open a few dc adapters just to see what was in them and there just an ac transformer and a four 1N4001 diodes and a cap
Welcome to the world of electronics !!! PSs are the best place to start, you get a lot of the basics without being overwhelmed. Nice clean job for your first project. If you need info feel free to ask. A lot of us here have been into electronics for a long time &amp; love to share what we've learned.(45 years myself ) Yes, started when I was 4 years old... NOT !! CHEERS!!!
Thanks, i got another project that i thinking about its converting a drill battery pack so that you can use a ac mains transformer (In its own housing) ive picked the LM338 Vreg witch in rated a 5A. I mainly use my drill at my bench and dont really need the battery, but its nice to have the best of both worlds. I was thinking build a 12V supply into the spare battery pack and use a DC Jack to input the ac. Do you think 5A will be enough? i had it running of a 2.5A PSU but once load was put onto the drill it was not very good

About This Instructable




More by Wizzkid1984:Homemade LM317 Bench Power Supply 
Add instructable to: