Head-Fi.org › Forums › Misc.-Category Forums › DIY (Do-It-Yourself) Discussions › My first completed PCB design, High End LM317 regulator! Ready to do the first PCB!
New Posts  All Forums:Forum Nav:

My first completed PCB design, High End LM317 regulator! Ready to do the first PCB! - Page 3

post #31 of 33
2/25/11 at 12:41am
Thread Starter 

OK. I browsed the Internet and found many helpful advices and instructions.

I was pretty sure my layout was correct so I decided to proceed. I used Press n Peel blue for toner transfer.

Here is the printed layout and prepared copper clad.

IMG_7907 [800x600].jpg

 

I filed the edges and used kitchen scrubber.

 

Then I let the board sit in etching solution for a minute as per Fred's advice.

IMG_7910%20%5B800x600%5D.jpg

 

I used iron on full heat and transferred the toner on my working table.

IMG_7912%20%5B800x600%5D.jpg

 

Pretty good for first try!! I fixed the output trace with a pen. Next time I must use more pressure, I think.

 

Here is the board after cleaning and drilling with 1 mm drill bit. Ready for parts placement.

IMG_7917%20%5B800x600%5D.jpg

 

After soldering

IMG_7927%20%5B800x600%5D.jpg

 

IMG_7930 [800x600].jpg


And it works right away. It outputs 26 volts for some reason. I used R1 120 ohm and 12V + 11V zeners. I also have the 1N4007 after the zeners. I don't understand what it does though.

 

I am very happy with the result. I use it now on my Pimeta v2. It replaced the breadboard version of the regulator. The previous version didn't have zener reference so that is new.

 

Thanks for the advices!

 

Next I would love to do a SMD board, because I found out that manual drilling is quite difficult to do accurately. It seemed to rip of traces very easily.

 

PS. I did a little mistake. My wall wart outputs 29V after rectification so that input electrolytic capacitors voltage rating has been exceeded. It hasn't exploded yet and isn't warm, but maybe Panasonic actually can be used a little over spec.

Reply
post #32 of 33
2/25/11 at 1:31am

Your output voltage is 12+11+0.7 (the 1N4007)+ 1,25 (the voltage across R1) = 25 but zeners aren't always very accurate so 26 doesn't surprise me much.  You could replace the 12V zener by a 10V one to get nearer to 24V.

 

For caps, I would use 35V rated at the input and at the output of the reg, unless you replace the zener; in which case, you could use 25V ones.

Reply
post #33 of 33
2/25/11 at 2:08am

Wow excellent results for your first PCB!

I've had the drilling problem before too. You can make the pads larger so that there is less chance of lifting the trace but if you want to make an SMD version, look for the SOT-223 packaged LM317:

 

SOT-223.jpg

 

The schematic would be the same, just different layout. Also 1206 size SMD resistors are a good size to start with, very easy to solder smily_headphones1.gif

Reply
New Posts  All Forums:Forum Nav:
  Return Home
Head-Fi.org › Forums › Misc.-Category Forums › DIY (Do-It-Yourself) Discussions › My first completed PCB design, High End LM317 regulator! Ready to do the first PCB!