This is a small size power supply with low cost and easy to make that only taking about 5 more hours. I was very happy with it and would share with you.

Power Supply Specifications

Input: 5v-16v/3A DC

Output: 1.3V - 15.5V/2 Amps

Step 1: Materials and Tools

Here is a list of materials and tools I used for this project.


2 x LM2596S DC-DC module link

2 x Voltage/Current DC0-100V LED meter link

2 x WXD3-13-2W-10K link

2 x D3-13-2W knob link

2 x 4MM banana jacks(Red + Black) link

2 x 4MM banana sockets(Red + Black) link

1 x switch 117S 8.5*13.5MM link

1 x Power Jack DC-022 DC 5.5mm 2.1mm link

1 x AMS1117-5V link

1 x 5V 30mm fan link

6 x 2.5mm/6mm screw

1 x DC adapter 16v / 3A, the voltage range between in 9v~16v would be better.


3D printer with PLA withe & gray color

Soldering iron

<p>Nice idea on using those multi turn potentiometers, that is going to help with setting your output very precisely without the need of having two separate course and fine adjustment knobs. The end result also looks pretty good!</p><p>The only thing that I'm concerned about are those cheap switching regulators. I'm pretty sure their performance is not going to be that good and the ripple and noise are going to be quite high. Obviously, that's not your fault since you aren't the one who build them or designed them. Anyway, the thing is that this can lead to problems if you are trying to power sensitive circuit like amplifiers for example, so you need to be aware of that. By the way, I'd love to see some ripple and noise measurements if you can.</p><p>Since you are not powering the power supply from batteries it might be a better choose to use linear regulators instead. If you mostly work with low power electronics their efficiency is not going to be an issue.</p>
<p>I am using this project just for arduino and ESP8266 modules study. It might not good enough, however it helps me the dual power source requirement. </p><p>It would be happy/appreciate that if someone who can modify or improve this project.</p>
<p>I was thinking about a more custom solution using a linear regulator <br>instead of a switching regulator module. If you're mostly working with <br>low power electronics like microcontrollers for example, a dual channel <br>power supply with a 0V to 15V voltage range and 800mA maximum current on<br> each channel should be more than enough.</p><p>From a quick search and<br> I found a very nice one, the <a href="http://www.linear.com/product/LT3042">LT3042</a> from Linear Technology. It has <br>ultra low noise capabilities and a very high power supply rejection <br>ration. It has a voltage range from 0V to 15V, not many linear <br>regulators can go down to 0V. The popular LM317 for example can go only <br>down to 1.25V. It has a programmable Power Good function which is a nice<br> bonus. It has a maximum of 200mA output current but it is parallelable,<br> which means you can put 4 of them in parallel to achieve an output <br>current of 800mA. There is even an application example circuit on page <br>25 of the <a href="http://cds.linear.com/docs/en/datasheet/3042fa.pdf#25">datasheet</a>. Putting many regulators in parallel also decreases <br>the noise even further. And finally it has a dropout voltage of only <br>350mV.</p><p>And about powering the regulators, you can use a <br>15V-0V-15V mains transformer combined with two full wave bridge <br>rectifiers and two big 2200uF capacitors. This will give you two DC <br>voltages of about 20V which is more than enough to power each channel. <br>And in case you wonder how you get 20V from 15V it's very simple. The <br>15V are AC, so after the rectification you will get a DC voltage equals <br>to 15VAC * sqrt(2) - 0.7V - 0.7V = 19.81VDC. The two -0.7V are the <br>voltage drops from the diodes.</p><p>The only thing that might be a <br>problem to you it is that it's only available on an SMD package, so if <br>you are not familiar with SMD soldering that might be an issue. Also, <br>the chip is a little expensive, I found it for $2.73 on LT's website and<br> for a dual channel PSU you need 8 of them. But that was just an <br>example, there are thousands of linear regulators out there, I only <br>searched for a couple of minutes and found this. If you do some research<br> yourself I'm sure you can find many alternatives. Any linear regulator <br>is going to be better than a switching one for your particular <br>application, even an LM137 will do the job if you don't care about the <br>dropout voltage and the voltage range that only goes down to 1.25V.</p>
wow, you are expert on the power. I will study it, thanks so much for providing the valuable information.
<p>Just noticed I made a small mistake on my previous comment, I meant to write 15V-0V-0V-15V transformer not 15V-0V-15V. Sorry about that, I hope I didn't confused you. I've also drawn a quick schematic to help you understand the concept better.</p><p>A power supply based to two isolated rails is very flexible. You can use it to power two different circuits while keeping them completely isolated. Or, you can connect the two rails in series and get a positive and a negative voltage, this can be quite handy for powering op amps. Or, you can just connect them in series to get a larger maximum voltage.</p>
<p>If you stick with the single polarity mode, might be a good idea to keep the ground terminal post on the left of the two variable outputs. That way the user cannot assume that you can stack/chain these as per a split design (typical used for powering analog opamp circuits etc.)<br><br>Another important point, if your source supply has a earth ground, it may feed through to the output, in which case you have to be careful that what you connect doesn't somehow cause a short in case it also has an earth ground that somehow ends up getting connected to the positive terminal.</p>
<p>If the two rails are electrically isolated like in the schematic I posted, you can chain them to achieve a reverse and a positive polarity, there is absolutely no issue with that. It's like stacking together two 9V batteries to get +9V and -9V. Basically, what you have is two separate power supplies in the form of one. You could even use two different transformers instead of a dual one if you wanted, it's exactly the same.</p><p>As for your second point, the best thing you could do is to connect the mains earth to the chassis and make it available via a separate fifth connector. That way the user can decide whether or not he wishes to mains earth reference his power supply output and where to connect the mains earth.</p>
<p>Absolutely, I do this myself...</p>
Unfortunately that won't work with this. This is a plastic chassis.
<p>Indeed, I wasn't talking though specifically about this particular project. It was more of a general discussion about how to design a good dual rail power supply. Of course you need a metal chassis because you want it to act as an EMI shield too.</p>
<p>No issues with your recommendation, I was actually commenting on the original design.</p>
Hmm,thats a good one!do u have any specific ideas to build the supply?right now i can definitely use a low noise low power supply
<p>As I said previously, if you want low noise the best solution is to go for a linear design, use a transformer to drop the high voltage to a usable level (e.g 12V), rectify it using a diode bridge, smooth it using a huge cap (its size is going to depend on your maximum current that you decided to design it for) and a linear regulator at the end. Regarding the regulator LT has a huge collection of them, one of my favorites is <a href="http://www.linear.com/product/LT3080">LT3080</a> as it has the ability to go down to 0V, but there are many options to choose from.</p><p>The disadvantaged of a linear design is obviously the lower efficiency compared to a switching one, since a linear regulator basically acts as a resistor, but for a lab power supply this should not be a problem. It's a piece of test equipment and efficiency is last thing that you care about.</p><p>If you want to build a dual rail PSU checkout the schematic I posted on my previous comments, that should be a good starting point. The only thing that is missing from it are the linear regulators and their passives, and that's because as I said there are tons of them to choose from.</p>
regarding the multi turn pots,yes they are a good idea but the problem with chinese ones is that they are not linear always but have few jumps during the rotation.<br>(not saying that they are not good,we studentys have to make dowith it,but the cheaper option is definately better than paying lots for tyhe ones fromBourn)<br><br>Regarding the Switch supplies,(harmonics and noise issues)the best example is HamRadio,one of my elmer mistakenly carried a converted ATX to a field day!lets just say he had more of a bad day than a field day :)<br>
<p>I made similar thing to change my LM350 with 2.5A 16V transformer and when i wanted to draw 2A from it it changed voltage from 10-12v and it wasnt really stable</p><p>Now im back to LM350 </p>
<p>Problem I have had with those panel meters doing something similar in the past, is they put the shunt in the negative line, so your 2 ground terminals are now not quite at the same voltage, putting the 2 grounds together will end up with the current readings being inaccurate.</p>
<p>yes, I found this problem also, did you fix it?</p>
<p>Great intractable !!! </p><p>I really wan&acute;t to build this :)</p><p>Could you please tell me the most important settings f&uuml;r the 3D printer like temperature, speed and so on?</p>
I am using PRUSA i3, the printer setting will be based your machine and filament. my setting, t:220&deg;c ,speed:50, density:20.
<p>Literally just put a fairly large eBay order in :D</p>
have fun on it.
<p>I change the fan direction with blow air out.</p>
<p>Folks there is no need to print anything. Just get a project box that is large enough and cut out the holes needed.</p>
<p>True, but the STLs are a really nice added touch to this Instructables, for those who have access to a 3D printer. Nicely done.</p>
Why do you need those monstrous and expensive 2 Watt potentiometers if you can use every random potentiometer with 10k resistance? And for those who are crying abot 3d printer in comments - you do not need one to make couple of holes in a plastic box.
<p>The potentiometers are 10 turn and much better to adjust.</p>
<p>yes, your hit my point, I like 10 turn.</p><p>For the holes on the front panel, I design it for USB port, however, it fails. I have removed it already.</p>
<p>Nice job, I like your approach. Looks like something I would be likely to do.</p><p>I see that you have a fan on the back. Hopefully it is trying to blow air out the back and not in. If it is blowing in, it will eventually fill the box with dust.</p><p>If there is a fan there should be vents somewhere else so that the air has a path both in and out of the box.</p>
<p>good idea, thanks.</p>
<p>I'll just break out my 3D printer... oh wait.. who the heck has one of those just knocking about? </p>
<p>https://www.3dhubs.com/ Bit of googling won't hurt next time.</p>
<p>To be fair, that IS a very handy link :-)</p><p>Not bad!</p>
<p>I think there's always a way to get what you need.<br>Happy to know you like the link.</p><p>Try to remember the &quot;Be nice&quot; comment policy :)</p>
Where I am, I can't get any of the printer.. but that's something I would love to try.
<p>The 3D printing is not necessary. Cut plain pieces of acrylic plate to size and glue them along the edges. Or even simpler, use paper impregnated with lacquer to create your own plastic-like material - won't be as sturdy as real plastic plates, but IMO strong enough for what you need.</p>
Everything bought and assembled . Might as well spend an extra dollar and buy complete
<p>I like these little voltage/current regulators but I have one problem with the ones I have used: they measure the current on the low side. As a result the two ground connectors are not really the same ground the differ by mv but if connected together the current readings are messed up. What is your experience?</p>
I haven't a precise equipment to do the test, but I like to know the answer if somebody do it.
<p>Neat project. I noticed the links, however went to a web store that is all in Chinese. But looking at the LED Voltage/Current meters, you could also get the parts from Banggood.com.</p>
This looks very useful for my teaching! But can you suggest a way of protecting the power supply with some sort of inbuilt electronic fuse? Some of my students will at some point short surquit whatever they are working on.
<p>The LM2596S DC-DC module has short protection, however, add a fuse is a good idea. </p>

About This Instructable




More by RegisHsu:Handy Power Supply [vPython] Spider Robot simulator [DIY] Spider Robot - PART II - Remote control 
Add instructable to: