You should add a high power dummy load on the power rail (in this case red 5V) to keep the power supply a little bit more stable for low amounts of current. I forgot to mention that.
I built this power supply a year ago, adding dummy load burns the connection wires , the load resistor is burned , and DC 400v capacitor also burned, it's not suitable for lab purposes. I tried removing short-circuit protection ic but mains supply is shorted I don't know why but it's lethal man.
Yeah but maybe just a 1 ohm would be good. It shouldn't be able to burn the wires then. Anyways, if you burn out the wires you are definetly doing something wrong. :)
There are only two things I would change about this design. Some power supplies require a minimum load on the 5v or 12v rail to keep the voltage outputs in range, so you should use a high-power dissipation resistor or a small static load to keep the PSU stable. In my case, I used an extra fan and some bright white LEDs to illuminate my workspace. The fan draws 12v current and the LEDs draw 5v. Second, since all of the ground lines are the same anyway, you may as well get a piece of aluminum or copper bar, drill holes along it, screw all of your negative terminals to it in a row, then connect all of the ground lines to this metal bar. That way, each negative terminal can have access to all of the ground lines, and you don't have to worry about partitioning out your ground lines according to which Vout you hope your highest current draw will be on..
@@konyaelod Yea I would love if Jaden made the video showcasing his tips, but yea....too late I would ask you tho, Jaden, are you talking about copper ground bus bar ? I was searching for it on Google and it seems to be what you are referring to in your second tip, care to elaborate ?
Great project. Last week I found working ATX power supply on the street and I want to make an adjustable power supply. Your tutorial is the best one I have found :D thank you very much! Amazing work!
Nice production quality, and effort. FYI the PWM SMPS controller circuit designed into ATX power supplies only uses 1 rail for the 2 comparators and feedback circuit. This means that all other voltage rails are regulated through magnetic coupling only. Most of these ATX bench supplies eventually fail because of this configuration. These supplies are designed as cheaply as possible for a very specific type of load. The load must always draw more current from the main rail as it is designed. The main rail is the rail with the highest current rating. If you understand this circuit topology you will also see why the extra voltage rails appear to drift a small amount as the load changes. Some supplies use additional linear regulators to limit this issue. Regardless, if you try to pull a considerable current from one of the extra rails while the main rail has a lower load, the SMPS controller doesn't have the ability to monitor and compensate for it directly. This is an easy way to cause the circuit to fail. If you want to understand SMPS controllers in depth the simplest starting point is a "Peak Mode" controller. These only have 1 comparator and feedback loop. They are far more simple to understand. Most 5v car-type phone chargers use the simplest configuration possible. These devices usually come with a MC34063 chip in a simple 9 component DC to DC Buck Converter configuration. The next easiest Peak Mode controller to find and modify are the power bricks for laptops/printers. You can make simple adjustable power supplies out of all of these by themselves by just adding a potentiometer in place of one of the feedback resistors. I've uploaded a couple examples before. I'm none monotized and no affiliation links. I'm just here to make friends and check out what other people with similar interests are doing :) Subscribed. All the best, -Jake
Yes of course, ALL power supplies are like that, because Jake knows them all. Especially this antiquated TL494 flyback design he's obviously talking about. Sorry, I don't mean it badly ... even in 1990 there was feedback on ALL low-voltage outputs possible. It then leads to an emergency shutdown if it is misused. ... or ATX1 and cheap, it doesn't matter ... any PC power supply ... the whole thing is a stupid idea to build a laboratory power supply with it. Including the *chopper* , uh I mean DC/DC converter. Who comes up with such nonsense? Actually, I say the same thing as Jake, but without flowers. I think that's an absolutely bad idea. A laboratory power supply, like proper measuring instruments, is a basic component of a laboratory. Without it, proper work is almost impossible and a torture. So why torpedo your own fun and success by saving money at the wrong end? Warning, wisdom: What do you need to build a decent power supply? A better power supply! And a decent measuring device that can tell you what kind of junk ... or not ... you've built. Edit: By the way, what also belongs to a do-it-yourself construction is a comprehensive measurement protocol. Otherwise the video is just a fairy tale hour ... at least when it comes to power supplies, the key data such as stability and ripple are important and worth knowing for the viewer. Really useless and strangely enough nobody does that with these botch power supplies. I wonder why?;)
@@dieSpinnt you sound like one of those guys that has all the $$$$$$"laboratory spec" gear but cant build shit ahahha ..... i dont see a problem using an atx supply and a cheap meter for diy stuff like playing with arduinos or repairing and tinkering with your own stuff, now if if you have a company and do circuit design or repairs for a living then maybe a quality comercial power supply would be recommended. as far as stability i did not see any deviations in voltage, the meter may be innacurate but it would display voltage chages if there were any and ripple is very easily minimized with a capacitor. i am sure nobody will be using a diy power supply to launch a rocket or to control a nuclear power plant.
I don't think you will get the full range of voltage unless you vary the input voltage into the step up, step down converter. Same for the amperage. It would be better to find an ATX power supply that uses the TL494 pwm chip and vary the resistance on its pin #1 with a 10k potentiometer.
I've got an old 200W PSU with a TL494CN pw modulator and also the TL494CN datasheet laying around somewhere. I'm going to try as soon as I have the occasion. Unfortunately varying the voltage doesn't work that well because capacitors on the board do not allow for voltages higher than 16V usually on the 12V rail and 10V on the 5V and 3V3. Replacing the capacitor with one rated for a higher voltage might as well screw up other settings. GreatScott! tried to hack an ATX power supply to make it output a variable voltage but ran against the same problem and ultimately failed because he tinkered with it a little too much. Here is the complete video: th-cam.com/video/oeNAhP-GIjo/w-d-xo.html In my opinion it would be better to fine-tune the three main rails with a 10k 10 turns potentiometer each, then trust an external step up- step down converter on the 12V rail to get more precise results; or as an alternative connect the converter on the 5V rail since usually this outputs more current than the others. Also, the sheer difference in current delivered / accepted by the standard rails (12V, 5V, 3V3 with a minimum of around 8 to 10 amps) and the "non standard" rails (-5V, -12V with an absolute maximum of 1A) should be put into attention when connecting them.
Nice guide. I followed it and built my own variable power supply, but put it in a nice metal case I got on ebay. Thanks for the lesson and the good explanations.
The Buck boost converter is too small for most ATX power supplies. I found one at Banggood that is 600 watts that will handle the amperage from the ATX power supply. Neat project.
Great video tutorial. Thank you for posting all the helpful links and for taking the time to record, edit and post your project. There are many of us who appreciate the effort it takes to create content on multiple sites. Cheers
The only issue I have with SMPS is the fact that you can't really do anything with an oscilloscope unless you use an isolation transformer. I built my power supply with a linear transformer. I just used an MOT rewound to 24v.
Thank you for a great, helpful and informative video. It is a shame small minded people make such a fuss about your less than $10 title and completely miss the useful information. We should all be encouraged by your resourcefulness to reuse scrape and old material for our DIY projects.
Very good. I bought my buck converter and meter from China / Hong Kong and I have a PSU somewhere. I can easily build something similar for less than £8
Awesome video. Thank you for presenting it in a clear and understandable fashion. The fact that you also included a computer PSU as the base supply was great since I have been a computer tech much longer than an electronics tech so PSU's I know. Now I know my next major project. :)
Your videos are very informative but I am confused on some basics. For example, only one power source is used, so why not use just one black banana plug for all the dedicated voltage plugs? This would tie in with the common ground copper-bus suggested below--or have I overlooked something?
Guys, I recommend you to search for local scrapyards. Depends on where you live. For a brand new PC you should definitely use a brand new 30$ power supply. But this project is made with a power supply from year 2000 or so… You can easily find those for 2 or 3$ because are old, low power (400W which now days is low) and the connectors are not useful any more. I can assure you I haven’t spent more than 10$ for this project. Plywood is 2$ a square meter so… and all the extra components are listed above. Thank you for everything, have a nice day.
Can I solder a normal 100 kOhm resistor to a 100 kOhm multiturn potentiometer in order to get to 200 kOhm? Can't find a 200 kOhm multiturn potentiometer! My step up booster uses the 204w trimmpot
TKS for sharing your knowledge. So if I want to put more Ampers I have to use another device, I would like to put 13,8V with 20 Ampers is that possible? TKS.
Great video! Questions: If you were making a bench power supply like this with a transformer instead of an ATX, and a 3-in-1 Adjustable DC Regulated Power Supply DIY Kit, how could you get 3.3, 5, and 12 volts for the fixed voltage outputs?
If I'm using a 300w ATX is it possible to get 12v 300w or 24v 300w? I work with LEDs and need the power. Why did you put the variable resistors the other way around to the display markings?
Watt is voltage times current. A 300W power supply at 12V will have a maximum current output of 300/12 = 25A. But maybe that's not the case because usually those supplies have multiple outputs and the output current might be a bit lower. So, the power (W) will always be the same but the current will change.
Electronoobs Thank you for the response. I was thinking of making a supply with a separate 3.3 and 5v and then using the 12v 18A 216W output separately connected to a buck/boost. Would it be a decent option or would I need to get a supply that can put out the voltage needed and then just using a buck?
Nice build. I built something similar years back & I've always wondered why more people don't just use an old PC power supply. They are everywhere & likely won't cost anything (literally free), they have EXTREMELY clean power outputs & have built in safety features that have saved a few of my projects. I was gonna mention building a dummy load on the 5V rail for general current stability, but see where you mention it in comments. I've been thinking of trying out the Arduino on my next build so I can add some extra features like a Signal Generator for TTL & mess around with RF, PWM & FM a bit (kinda make a built in LCR & ESR meter out of it as well). Was wondering if you've done anything like that because my programming is in it's infant stage? Great vid, very clean build. Good job
Hi, I have a voltmeter ammeter with yellow black and red wires and black and red, if I connect the way you in diagram it shorts and shuts psu,can you tell how should I connect correctly to make it work for variable output?
Hi please give me some advice. I have a computer power supply that is rated at 350W. I want to put a pair of USB plugs onto it to utalize the 3.3v 20A, 5v x 20A, 5v x 2A, and the 2 x 12v x 312W outputs. My plan is to do 2 x 5v USB, 1 x 3.3v 1 x 12 v to power a T12 soldering iron and the other a 12v a buck buck boosted supply. What would you recommended?
1. The +12v of the power supply is rated at 8A and the buck boost supports only 4A. Isn't that a problem? or is it 4 drawn not input? 2. Can you make a video of it running a 12v/24v motor at 4A? or just test it and tell me that it works
I built one of these a while back and the PSU killed itself. Seems your supposed to add a constant load which is always on? Do you know what it kills and why it needs this dummy load? Thanks
A few questions: I see you have two +5V outputs with different amperages so my guess is that you just connected one wire to the 2A output and 5 to the 26A one, since the total +5V of your power supply is rated 30A. Is that so? Plus, I have a 650W power supply (+3,3/24A, +5V/30A, +12V/52A) I am thinking of using like yours, but the voltage with the more amps is the +12V one, so I guess the dummy load would have to go there; but does it matter where you put it on the circuit and its value? Because you only mention it in your comment but not in the vid, so I wonder.
Hello, I did everything like described in the video but when i turn on the power supplie it starts workind and then it shuts down automatically. I can tell by the fan that as just the time to start. I Checked the connections and the wiring twice. ANY idea ? Btw thank you for this great tutorial !
Hey man, you should you a dummy load...like an extra fan ou a car bulb lamp. The power supply shuts off because is no load and automatic shuts off. Trie to connect something in the 12 v or 5 v and see if shuts down...good luck
@@droquesteni Hey thank you for your answer ! I tried to had a dummy load on the 5v rail but it didn't helped. So I rechecked everything and made some tests by eliminating the components one by one. It appears that the problem come from the digital display. Everything works fine when I by pass it. I have 3 of them so I tried with each one, and the atx always shuts down... Maybe I'm wiring it wrong but I did excatly the same wiring as it is in the video. I'm a bit confused here, just can't figure it out... Thanks you for your help
@@raonimoisan4614 no problem. So if your problem is from the display, be aware that if you buy this king of display lcd on ebay they are different! I realized that the display i bought have the same 2 connections BUT the connection to the amp meter the 2 large cables red and black if for only measurement of the amps! The other connection have 3 wires red, black and yeallow. So this connetion red and black is for feed the lcd to 5v, the yellow wire if for volts measurement! So, yellow wire to + of the dc boost for example, to the 2 large wires, red wire to the - of the boost and the black wire to the ouput you want measure... hope that helps! take care!
@@raonimoisan4614 Chances are that you're wiring your LCD the wrong way. I had the same issue, then a more careful sheet reading and a correct wiring fixed the problem.
The holes for the fan should be larger. Like 6 or 8 mm or so. Have a try breathing through those 1mm holes. It's just like there are no holes. ( Though don't breath in through just drilled holes ! You'll get crap in your lungs. Got experience on that. )
I got the DSW5020, the 20 amp version. Worked for awhile. Suddenly I can no longer test my laser diodes..can't get more than 1.25 amps out of it even when I set the max amps to 5. Really strange. I tried changing the power source but that did not help either. No longer works.
how do you get 5V 2A? or is it -5V? Furthermore, there are some differences between current label from PSU and your printed label. was it misprinted or does it really provide 20A @ 3.3V and 17A @ 12V? your PSU only provide 14A @ 3.3V and 8A @ 12V.
Hi, very nice video! I am planning to build up a similar one, thanks for the advice☺👍. I have a question, can I use the RM065 10k potentiometer instead of this one in the video? Thanks
Just what I've been looking for! However, I am a noob and a little confused. Does the output enable switch in the schematic have to be 'ON' to get variable output from the buck-boost converter? Also, will the LCD function when that switch is 'OFF'? I know, very stupid questions that are covered by the video but my infant brain won't recognize them! Many thanks!
Hello. Your tutorial is great,but i have some questions: i have some power suplys from old laptops, one of them with 15v, and is small,perfect for this project. Do you think is possible to use it,instead of a desktop power suply?? Another question, if i going to use the laptop psu, do you think i can connect the volt/ampmeter directly to 15v input,because it doesn´t have 5v power rail like desktop psu?From i understand in specifications,it says:"Power supply range: DC4-30.0V" And 3rd question, do you think i can use this project(made from desktop or laptop,doesnt matter) to detect shorts in circuits,like laptop boards?
Great video! Thanks! One thing though, is the links to the parts you have are mostly gone now. The listing has ended, or there sold out, or just gone for good. Do you mind updating that page?
Nice project, if I didn't already have a bench supply, I might try it. -- Also, I hate to say it, but sorry man, you're not going to be getting 26A out of a single 5V wire. -- You really need to pair them all up to push that much amperage through... -- Also, I doubt those banana plugs are rated for more than 10A each anyway... -- Also you should put the buck/boost converter into the airflow path of the power supply fan. (Or add another fan that cools it.)
is there a safety just in case I accidentally short the power supply when working on something. plus I have 2 10 Ohm 10 v dummies and a extra fan is that too much? can you put a extra capacitor to smooth out the signal?
Hi there. Your Schematic/Wiring Diagram has a BIG Fail (at least for maybe "newbees") - if you're wiring up following your Schematic, then I think it will blow up the Buck/Boost-Converter. Because the Red & Black wire for the Output you have reversed in your Schematic. You are doing it right in the video - but wrong in the Schematic ;-) Im btw. in the middle of building on of those for my self. Thx. a bunch for the video! Nice and easy to follow.
Can I just solder the green and black wire together? That way, it will always be turned on as soon as the PSU is turned on.The PSU already has an on/off switch after all.
I know that i am really late but i wanted to ask if i wanted finer control for the voltage how could i do that? Could i just add a second pontentimeter of higher resistance value to the original one?
I have a atx power supply that will not take 6amps without turning it off then connecting the load then it works. if i dont turn it off before i connect the load it shuts down. any ideas?
Nice job. I have most of this built previously but liked your buck con. better. It looks like your schematic shows a black wire on the positive output of the buck. Is that correct, it does not match video connections. :)
Hm. I need a power supply. But I have a PC power supply left over. And I have two voltage regulators left over from another project. Not sure if I can get current limitations though.
Electronoobs , first of all, great video and it is very inspiring. However, please correct me if I am wrong, but I think the output terminal connection to the volt/amp meter are switched around on you diagram right? ..which must be a mistake ? ....I dont have the component at hand (yet) just watching your diagram and the products from ebay...i could be wrong
@@ELECTRONOOBS , sry i meant the boost converter output side towards the meter, the image is mirrored so it is bit difficult to se. But as I see it from the picture then the terminal close o the pot meter is + positive (around 6:42 in the vid), and the one close to LM2577S is -negative, right?.
Great project and very well explained. One of the best DIY variable PS videos I have seen. Question: When I look up the DC convertor you used, it specifies the a max input current of 10A. Is it Ok to use this with the ATX PSU, as the +12V rail provides up to 8A current?
Thankew for such wonderful DIY. My SMPS is from 2000 as well however my capacitors near the AC supply end were burned , they are 200v 330uf. I tried to search for these online but found none. If you had faced this I wonder huv did you find these capacitors.
Great video, I got an issue, using a different model lcd, looks the same but its a bit different wiring, dsn-vc288, the problem I have is that I can only seem to see volts or amps not at the same time, i have to remove the thick red wire (amps) and connect the (thin) yellow wire (volts) but cant connect them both.
I think the schematic is wrong for the vc288. The thin red+black wires supply the meter (must be 5v or more). The thick red+black measure the current in the -ve return path (so it can measure current flowing from supply module - the two thick wires are connected together by a very low ohm shunt inside the meter). The thin yellow sense wire goes to +ve terminal to measure voltage at +ve terminal. The thin black wire and the thick black wire should both be at the same 0V potential. diyprojects.eu/how-to-wire-digital-dual-display-volt-and-ammeter/
I like the tutorial! I'd like to know if you figured out what the center potentiometer does? I bought 3 of the boards from ebay and asked the seller what center potentiometer does. He didn't understand my question. I tried to use google translate to help with the explanation, but I never did get an answer to my question. I'm concerned about adjusting the center pot without knowing what I'm changing. Thanks for your time in replying. Keep up the great work!
ae01.alicdn.com/kf/UT8xg1BXbJXXXagOFbX3/220353225/UT8xg1BXbJXXXagOFbX3.jpg One limits the current output so the module will have the output actiuvated but the current limited. The other one will detect the limit of current that you set and turn the module off when that limit is reached (and turn on the red LED). I recommend to leave the middle one how it is so you have the full range of output current.
Hi, do you have a scope? I tried a buck/boost module like this and found it to be pretty much unusable (at least for a bench supply) because of the ripple. I'm wondering if you saw the same with this module.
If the boost could deleiver let's say 2 amps of current and you put a load that requieres more then you will have a big ripple and also could burn the module. But usually, the output capacitor should avoid the ripple quite well and you nshould have a very steady output.
Greetings once again. My Power Supply build is almost complete. During my initial test I connected a PC fan to load and when I increased Voltage to around 12V the fan turned on and the Voltmeter read 12.00 and the Ammeter read 0.40. I could increase and decrease voltage but the I could not control current. Is this to be expected or do I possibly have a bad Pot? Thanks again, and I'm going to enjoy my new hobby!
With the I pot you should fix a maximum current. If you can't lower the maximum value something might be wrong, could be the boost/buck converter, could be the pot.
A couple of questions. Why solder multiple 12v cables to the input of the converter? Why not just one 12v cable? Is it just for redundancy? Also, would you pick the the highest voltage output from the pc power supply or would it be better to pick the highest amp output on the pc supply. Last question, what is the middle potentiometer on the buck boost used for ? if the other two are used for voltage and ampage adjustment. If anyone could help me with this. It would be much appreciated!
Heu bro. I want to buy a step-up and a step-down converter. They should output the same voltage ranges? The step-down converter output from 1.3 to 35 Volts and the step-up converter from 5-24volts.
You should add a high power dummy load on the power rail (in this case red 5V) to keep the power supply a little bit more stable for low amounts of current. I forgot to mention that.
OK, got you!
I built this power supply a year ago, adding dummy load burns the connection wires , the load resistor is burned , and DC 400v capacitor also burned, it's not suitable for lab purposes.
I tried removing short-circuit protection ic but mains supply is shorted I don't know why but it's lethal man.
Sounds like you did something wrong, the resistance of your load might have been too big.
karlpc200 nope, I watched so many vids in utube they are using 10ohm resistor .
Yeah but maybe just a 1 ohm would be good. It shouldn't be able to burn the wires then. Anyways, if you burn out the wires you are definetly doing something wrong. :)
There are only two things I would change about this design. Some power supplies require a minimum load on the 5v or 12v rail to keep the voltage outputs in range, so you should use a high-power dissipation resistor or a small static load to keep the PSU stable. In my case, I used an extra fan and some bright white LEDs to illuminate my workspace. The fan draws 12v current and the LEDs draw 5v.
Second, since all of the ground lines are the same anyway, you may as well get a piece of aluminum or copper bar, drill holes along it, screw all of your negative terminals to it in a row, then connect all of the ground lines to this metal bar. That way, each negative terminal can have access to all of the ground lines, and you don't have to worry about partitioning out your ground lines according to which Vout you hope your highest current draw will be on..
I have 2 10 w 10 v load resistors and an extra fan is that to much? and can you use a extra capacitor to smooth out the signal?
You can always set up fan to suck up soldering fumes on top of the unit.
Brilliant tips!
Please consider a short video on this subject.
Cheers m8
@@cri8tor that would be nice
@@konyaelod Yea I would love if Jaden made the video showcasing his tips, but yea....too late
I would ask you tho, Jaden, are you talking about copper ground bus bar ? I was searching for it on Google and it seems to be what you are referring to in your second tip, care to elaborate ?
Great project. Last week I found working ATX power supply on the street and I want to make an adjustable power supply. Your tutorial is the best one I have found :D thank you very much! Amazing work!
Nice production quality, and effort.
FYI the PWM SMPS controller circuit designed into ATX power supplies only uses 1 rail for the 2 comparators and feedback circuit. This means that all other voltage rails are regulated through magnetic coupling only. Most of these ATX bench supplies eventually fail because of this configuration. These supplies are designed as cheaply as possible for a very specific type of load. The load must always draw more current from the main rail as it is designed. The main rail is the rail with the highest current rating. If you understand this circuit topology you will also see why the extra voltage rails appear to drift a small amount as the load changes. Some supplies use additional linear regulators to limit this issue. Regardless, if you try to pull a considerable current from one of the extra rails while the main rail has a lower load, the SMPS controller doesn't have the ability to monitor and compensate for it directly. This is an easy way to cause the circuit to fail.
If you want to understand SMPS controllers in depth the simplest starting point is a "Peak Mode" controller. These only have 1 comparator and feedback loop. They are far more simple to understand. Most 5v car-type phone chargers use the simplest configuration possible. These devices usually come with a MC34063 chip in a simple 9 component DC to DC Buck Converter configuration. The next easiest Peak Mode controller to find and modify are the power bricks for laptops/printers. You can make simple adjustable power supplies out of all of these by themselves by just adding a potentiometer in place of one of the feedback resistors.
I've uploaded a couple examples before. I'm none monotized and no affiliation links. I'm just here to make friends and check out what other people with similar interests are doing :)
Subscribed.
All the best, -Jake
Thank you for your sincere comment!
Very helpful to know... Question... What if I only used the main rail and just varied that
@@ELECTRONOOBS can u change the current? If yes min/ max
Yes of course, ALL power supplies are like that, because Jake knows them all. Especially this antiquated TL494 flyback design he's obviously talking about. Sorry, I don't mean it badly ... even in 1990 there was feedback on ALL low-voltage outputs possible. It then leads to an emergency shutdown if it is misused.
... or ATX1 and cheap, it doesn't matter ... any PC power supply ... the whole thing is a stupid idea to build a laboratory power supply with it. Including the *chopper* , uh I mean DC/DC converter.
Who comes up with such nonsense? Actually, I say the same thing as Jake, but without flowers. I think that's an absolutely bad idea. A laboratory power supply, like proper measuring instruments, is a basic component of a laboratory. Without it, proper work is almost impossible and a torture. So why torpedo your own fun and success by saving money at the wrong end?
Warning, wisdom: What do you need to build a decent power supply? A better power supply! And a decent measuring device that can tell you what kind of junk ... or not ... you've built.
Edit: By the way, what also belongs to a do-it-yourself construction is a comprehensive measurement protocol. Otherwise the video is just a fairy tale hour ... at least when it comes to power supplies, the key data such as stability and ripple are important and worth knowing for the viewer. Really useless and strangely enough nobody does that with these botch power supplies. I wonder why?;)
@@dieSpinnt you sound like one of those guys that has all the $$$$$$"laboratory spec" gear but cant build shit ahahha ..... i dont see a problem using an atx supply and a cheap meter for diy stuff like playing with arduinos or repairing and tinkering with your own stuff, now if if you have a company and do circuit design or repairs for a living then maybe a quality comercial power supply would be recommended. as far as stability i did not see any deviations in voltage, the meter may be innacurate but it would display voltage chages if there were any and ripple is very easily minimized with a capacitor. i am sure nobody will be using a diy power supply to launch a rocket or to control a nuclear power plant.
I don't think you will get the full range of voltage unless you vary the input voltage into the step up, step down converter. Same for the amperage. It would be better to find an ATX power supply that uses the TL494 pwm chip and vary the resistance on its pin #1 with a 10k potentiometer.
or you can buy TL494 chip and do it yourself
I've got an old 200W PSU with a TL494CN pw modulator and also the TL494CN datasheet laying around somewhere. I'm going to try as soon as I have the occasion.
Unfortunately varying the voltage doesn't work that well because capacitors on the board do not allow for voltages higher than 16V usually on the 12V rail and 10V on the 5V and 3V3. Replacing the capacitor with one rated for a higher voltage might as well screw up other settings. GreatScott! tried to hack an ATX power supply to make it output a variable voltage but ran against the same problem and ultimately failed because he tinkered with it a little too much. Here is the complete video:
th-cam.com/video/oeNAhP-GIjo/w-d-xo.html
In my opinion it would be better to fine-tune the three main rails with a 10k 10 turns potentiometer each, then trust an external step up- step down converter on the 12V rail to get more precise results; or as an alternative connect the converter on the 5V rail since usually this outputs more current than the others. Also, the sheer difference in current delivered / accepted by the standard rails (12V, 5V, 3V3 with a minimum of around 8 to 10 amps) and the "non standard" rails (-5V, -12V with an absolute maximum of 1A) should be put into attention when connecting them.
Nice guide. I followed it and built my own variable power supply, but put it in a nice metal case I got on ebay. Thanks for the lesson and the good explanations.
I've built a very similar power supply based off a 450W ATX. It's smaller because I cut holes in the power supply box itself.
Yours looks great.
The Buck boost converter is too small for most ATX power supplies. I found one at Banggood that is 600 watts that will handle the amperage from the ATX power supply. Neat project.
Wow this guy is great
I made it and it works PERFECTLY , thank you for this tutorial ;)
Great video tutorial.
Thank you for posting all the helpful links and for taking the time to record, edit and post your project.
There are many of us who appreciate the effort it takes to create content on multiple sites.
Cheers
The only issue I have with SMPS is the fact that you can't really do anything with an oscilloscope unless you use an isolation transformer. I built my power supply with a linear transformer. I just used an MOT rewound to 24v.
great vid!
Nice video nice information about the price it’s over $20 I don’t know how you came up with $10 approximately but it’s nice thank you
In my country it is near 6$
Great video. I think this will be my first electronics project
Thank you for a great, helpful and informative video. It is a shame small minded people make such a fuss about your less than $10 title and completely miss the useful information. We should all be encouraged by your resourcefulness to reuse scrape and old material for our DIY projects.
great diy project need it on the job, build it today , works fine , but a load was needed and i like it cheap dirty and works great.
Very good. I bought my buck converter and meter from China / Hong Kong and I have a PSU somewhere. I can easily build something similar for less than £8
Awesome video. Thank you for presenting it in a clear and understandable fashion. The fact that you also included a computer PSU as the base supply was great since I have been a computer tech much longer than an electronics tech so PSU's I know. Now I know my next major project. :)
Will there be any problems if we use transformer as power supply for this module? Also, will we get noise free output even if we use smps as suppy?
Your videos are very informative but I am confused on some basics. For example, only one power source is used, so why not use just one black banana plug for all the dedicated voltage plugs? This would tie in with the common ground copper-bus suggested below--or have I overlooked something?
Nice video but you really have to increase your soldering job..
My eyes are bleeding bro.
I could not agree more!
Definitely, that soldering is gash!
Less than $10??? The first item on that list is $35.99!
I suspect this is one of those "Less than $10 if you already have all the parts lying around" kind of deals.
he does say he picked it up as scrap for $2
Yeah, same than "How to build sports car less than $100". Then repaints Lamborghini that he already own..
Guys, I recommend you to search for local scrapyards. Depends on where you live. For a brand new PC you should definitely use a brand new 30$ power supply. But this project is made with a power supply from year 2000 or so… You can easily find those for 2 or 3$ because are old, low power (400W which now days is low) and the connectors are not useful any more. I can assure you I haven’t spent more than 10$ for this project. Plywood is 2$ a square meter so… and all the extra components are listed above. Thank you for everything, have a nice day.
Isaac Kvasager yup
So the regulator can go up to 3Amps, but the power supply can go up to 30amps. Did you use the 30Amps output or not? Did you use only the 12V output?
Can I solder a normal 100 kOhm resistor to a 100 kOhm multiturn potentiometer in order to get to 200 kOhm? Can't find a 200 kOhm multiturn potentiometer! My step up booster uses the 204w trimmpot
Interesting and detailed explanation, but wouldn't it be wise to put fuses somewhere in there? Just asking.
Great explanation, and your website and links are great!
Excellent video, by watching I was able to resolve my wiring issue with the same V/A meter. Thanks. Keep broadcasting
TKS for sharing your knowledge. So if I want to put more Ampers I have to use another device, I would like to put 13,8V with 20 Ampers is that possible? TKS.
Great video! Questions: If you were making a bench power supply like this with a transformer instead of an ATX, and a 3-in-1 Adjustable DC Regulated Power Supply DIY Kit, how could you get 3.3, 5, and 12 volts for the fixed voltage outputs?
No fuses?
The fan blows the air in or sucks out?
If I'm using a 300w ATX is it possible to get 12v 300w or 24v 300w?
I work with LEDs and need the power.
Why did you put the variable resistors the other way around to the display markings?
Watt is voltage times current. A 300W power supply at 12V will have a maximum current output of 300/12 = 25A. But maybe that's not the case because usually those supplies have multiple outputs and the output current might be a bit lower. So, the power (W) will always be the same but the current will change.
Electronoobs Thank you for the response. I was thinking of making a supply with a separate 3.3 and 5v and then using the 12v 18A 216W output separately connected to a buck/boost. Would it be a decent option or would I need to get a supply that can put out the voltage needed and then just using a buck?
I'm a little confused. Why do you have a switch for the variable connectors?
Nice build. I built something similar years back & I've always wondered why more people don't just use an old PC power supply. They are everywhere & likely won't cost anything (literally free), they have EXTREMELY clean power outputs & have built in safety features that have saved a few of my projects. I was gonna mention building a dummy load on the 5V rail for general current stability, but see where you mention it in comments. I've been thinking of trying out the Arduino on my next build so I can add some extra features like a Signal Generator for TTL & mess around with RF, PWM & FM a bit (kinda make a built in LCR & ESR meter out of it as well). Was wondering if you've done anything like that because my programming is in it's infant stage? Great vid, very clean build. Good job
Great work sir
Hi, I have a voltmeter ammeter with yellow black and red wires and black and red, if I connect the way you in diagram it shorts and shuts psu,can you tell how should I connect correctly to make it work for variable output?
Hi please give me some advice. I have a computer power supply that is rated at 350W. I want to put a pair of USB plugs onto it to utalize the 3.3v 20A, 5v x 20A, 5v x 2A, and the 2 x 12v x 312W outputs.
My plan is to do 2 x 5v USB, 1 x 3.3v 1 x 12 v to power a T12 soldering iron and the other a 12v a buck buck boosted supply. What would you recommended?
1. The +12v of the power supply is rated at 8A and the buck boost supports only 4A. Isn't that a problem? or is it 4 drawn not input?
2. Can you make a video of it running a 12v/24v motor at 4A? or just test it and tell me that it works
I built one of these a while back and the PSU killed itself. Seems your supposed to add a
constant load which is always on? Do you know what it kills and why it needs this
dummy load? Thanks
Is it xl4016 based buck converter ?
Is the buck boost module still works pls pls tell
A few questions: I see you have two +5V outputs with different amperages so my guess is that you just connected one wire to the 2A output and 5 to the 26A one, since the total +5V of your power supply is rated 30A. Is that so?
Plus, I have a 650W power supply (+3,3/24A, +5V/30A, +12V/52A) I am thinking of using like yours, but the voltage with the more amps is the +12V one, so I guess the dummy load would have to go there; but does it matter where you put it on the circuit and its value? Because you only mention it in your comment but not in the vid, so I wonder.
No link for stuff that you use?
Hello,
I did everything like described in the video but when i turn on the power supplie it starts workind and then it shuts down automatically. I can tell by the fan that as just the time to start. I Checked the connections and the wiring twice. ANY idea ? Btw thank you for this great tutorial !
Hey man, you should you a dummy load...like an extra fan ou a car bulb lamp. The power supply shuts off because is no load and automatic shuts off. Trie to connect something in the 12 v or 5 v and see if shuts down...good luck
@@droquesteni Hey thank you for your answer ! I tried to had a dummy load on the 5v rail but it didn't helped. So I rechecked everything and made some tests by eliminating the components one by one. It appears that the problem come from the digital display. Everything works fine when I by pass it.
I have 3 of them so I tried with each one, and the atx always shuts down...
Maybe I'm wiring it wrong but I did excatly the same wiring as it is in the video. I'm a bit confused here, just can't figure it out...
Thanks you for your help
@@raonimoisan4614 no problem. So if your problem is from the display, be aware that if you buy this king of display lcd on ebay they are different! I realized that the display i bought have the same 2 connections BUT the connection to the amp meter the 2 large cables red and black if for only measurement of the amps! The other connection have 3 wires red, black and yeallow. So this connetion red and black is for feed the lcd to 5v, the yellow wire if for volts measurement! So, yellow wire to + of the dc boost for example, to the 2 large wires, red wire to the - of the boost and the black wire to the ouput you want measure... hope that helps! take care!
@@raonimoisan4614 Chances are that you're wiring your LCD the wrong way. I had the same issue, then a more careful sheet reading and a correct wiring fixed the problem.
The holes for the fan should be larger. Like 6 or 8 mm or so. Have a try breathing through those 1mm holes. It's just like there are no holes. ( Though don't breath in through just drilled holes ! You'll get crap in your lungs. Got experience on that. )
I got the DSW5020, the 20 amp version. Worked for awhile. Suddenly I can no longer test my laser diodes..can't get more than 1.25 amps out of it even when I set the max amps to 5. Really strange. I tried changing the power source but that did not help either. No longer works.
how do you get 5V 2A? or is it -5V? Furthermore, there are some differences between current label from PSU and your printed label. was it misprinted or does it really provide 20A @ 3.3V and 17A @ 12V? your PSU only provide 14A @ 3.3V and 8A @ 12V.
Recently discovered your channel. Like the videos I've watched so far. Keep up the good work.
Use 15 watt buck/boost converter with 300 wat atx power supply?
The link for buck-boost converter doesn't work, is there any alternative for that ?
Just superb sir.a most butifullvand brilliant build.keep up the great work.
Hi, very nice video! I am planning to build up a similar one, thanks for the advice☺👍. I have a question, can I use the RM065 10k potentiometer instead of this one in the video? Thanks
Just what I've been looking for! However, I am a noob and a little confused. Does the output enable switch in the schematic have to be 'ON' to get variable output from the buck-boost converter? Also, will the LCD function when that switch is 'OFF'? I know, very stupid questions that are covered by the video but my infant brain won't recognize them! Many thanks!
Hello. Your tutorial is great,but i have some questions: i have some power suplys from old laptops, one of them with 15v, and is small,perfect for this project. Do you think is possible to use it,instead of a desktop power suply?? Another question, if i going to use the laptop psu, do you think i can connect the volt/ampmeter directly to 15v input,because it doesn´t have 5v power rail like desktop psu?From i understand in specifications,it says:"Power supply range: DC4-30.0V" And 3rd question, do you think i can use this project(made from desktop or laptop,doesnt matter) to detect shorts in circuits,like laptop boards?
Great video! Thanks! One thing though, is the links to the parts you have are mostly gone now. The listing has ended, or there sold out, or just gone for good. Do you mind updating that page?
Nice project, if I didn't already have a bench supply, I might try it. -- Also, I hate to say it, but sorry man, you're not going to be getting 26A out of a single 5V wire. -- You really need to pair them all up to push that much amperage through... -- Also, I doubt those banana plugs are rated for more than 10A each anyway... -- Also you should put the buck/boost converter into the airflow path of the power supply fan. (Or add another fan that cools it.)
This bench power suply can be limit voltage
A or B pots are you used?
Can we use step down buck converter
Can we get noise free output from this power supply so we can test audio amplifier boards also?
is there a safety just in case I accidentally short the power supply when working on something. plus I have 2 10 Ohm 10 v dummies and a extra fan is that too much? can you put a extra capacitor to smooth out the signal?
Hi there. Your Schematic/Wiring Diagram has a BIG Fail (at least for maybe "newbees") - if you're wiring up following your Schematic, then I think it will blow up the Buck/Boost-Converter. Because the Red & Black wire for the Output you have reversed in your Schematic. You are doing it right in the video - but wrong in the Schematic ;-)
Im btw. in the middle of building on of those for my self.
Thx. a bunch for the video! Nice and easy to follow.
I clicked the like button twice.
Can I just solder the green and black wire together? That way, it will always be turned on as soon as the PSU is turned on.The PSU already has an on/off switch after all.
I don't understand if you're voltage converter can only handle 3:00 amps how do you have all the buttons for or is that not part of the variable part
Only the first connectors are variable. The other are fixed values directly from the supply and those haev high current
@@ELECTRONOOBS gotcha thanx...
I know that i am really late but i wanted to ask if i wanted finer control for the voltage how could i do that? Could i just add a second pontentimeter of higher resistance value to the original one?
I can't tell that you're a "noob" because you did it in a professional way. :D
ANTHONY CABALLERO lol. it's for noobs not that I'm a noob. I was a noob when I've started electronoobs
You really did a great job on that power supply :D
I like the way you say converter.
I have a atx power supply that will not take 6amps without turning it off then connecting the load then it works. if i dont turn it off before i connect the load it shuts down. any ideas?
which software you are use for design schematic diagram? pls tell me.
Nice job. I have most of this built previously but liked your buck con. better. It looks like your schematic shows a black wire on the positive output of the buck. Is that correct, it does not match video connections. :)
Good
Is it really variable if it only does set voltages.
It is definitely not a fixed value supply... Lol. And it could set current limit as well.
Hello. Can i use a bench power like this to find short circuits in laptop motherboards? Use it to inject tension and see if have anormal consunptions?
Hm. I need a power supply. But I have a PC power supply left over. And I have two voltage regulators left over from another project.
Not sure if I can get current limitations though.
Nice
Electronoobs
, first of all, great video and it is very inspiring. However, please correct me if I am wrong, but I think the output terminal connection to the volt/amp meter are switched around on you diagram right? ..which must be a mistake ? ....I dont have the component at hand (yet) just watching your diagram and the products from ebay...i could be wrong
Te diagram is correct. The problem is that there are different colors cables for other modules on eBay... Sometimes they use yellow, blue and so on...
@@ELECTRONOOBS , sry i meant the boost converter output side towards the meter, the image is mirrored so it is bit difficult to se. But as I see it from the picture then the terminal close o the pot meter is + positive (around 6:42 in the vid), and the one close to LM2577S is -negative, right?.
Great project and very well explained. One of the best DIY variable PS videos I have seen.
Question: When I look up the DC convertor you used, it specifies the a max input current of 10A. Is it Ok to use this with the ATX PSU, as the +12V rail provides up to 8A current?
Yes it is ok. That's the max current it could withstand. If you apply less there should be no problem. Keep up!
I have question if I apply 12 5a at the input of the buck converter what is the output voltage and current
I LOVE THIS PROJECT :D
video is well done
Thankew for such wonderful DIY. My SMPS is from 2000 as well however my capacitors near the AC supply end were burned , they are 200v 330uf. I tried to search for these online but found none. If you had faced this I wonder huv did you find these capacitors.
underrated channel ...
Hi thanks for the video. I am going to build a similar one but I have a question. Can I also use a xl6009 lm2577 step up-down converter up to 4A?
how many amps?
love your videos.
Great video, I got an issue, using a different model lcd, looks the same but its a bit different wiring, dsn-vc288, the problem I have is that I can only seem to see volts or amps not at the same time, i have to remove the thick red wire (amps) and connect the (thin) yellow wire (volts) but cant connect them both.
I think the schematic is wrong for the vc288. The thin red+black wires supply the meter (must be 5v or more). The thick red+black measure the current in the -ve return path (so it can measure current flowing from supply module - the two thick wires are connected together by a very low ohm shunt inside the meter). The thin yellow sense wire goes to +ve terminal to measure voltage at +ve terminal. The thin black wire and the thick black wire should both be at the same 0V potential. diyprojects.eu/how-to-wire-digital-dual-display-volt-and-ammeter/
I like the tutorial! I'd like to know if you figured out what the center potentiometer does? I bought 3 of the boards from ebay and asked the seller what center potentiometer does. He didn't understand my question. I tried to use google translate to help with the explanation, but I never did get an answer to my question. I'm concerned about adjusting the center pot without knowing what I'm changing. Thanks for your time in replying. Keep up the great work!
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One limits the current output so the module will have the output actiuvated but the current limited. The other one will detect the limit of current that you set and turn the module off when that limit is reached (and turn on the red LED). I recommend to leave the middle one how it is so you have the full range of output current.
Led module Positive and negative is connect each other by that steel bar, Did you un-connect them?
Hi, do you have a scope? I tried a buck/boost module like this and found it to be pretty much unusable (at least for a bench supply) because of the ripple. I'm wondering if you saw the same with this module.
If the boost could deleiver let's say 2 amps of current and you put a load that requieres more then you will have a big ripple and also could burn the module. But usually, the output capacitor should avoid the ripple quite well and you nshould have a very steady output.
Nice video, how did you make the schematics ? Did you used some software?
how would i add a on/off switch to the prebuilt power supply that you buy and could i hook up a 12v power supply to the input??
Is there anything like a small current limiting circuit ?
Greetings once again. My Power Supply build is almost complete. During my initial test I connected a PC fan to load and when I increased Voltage to around 12V the fan turned on and the Voltmeter read 12.00 and the Ammeter read 0.40. I could increase and decrease voltage but the I could not control current. Is this to be expected or do I possibly have a bad Pot? Thanks again, and I'm going to enjoy my new hobby!
With the I pot you should fix a maximum current. If you can't lower the maximum value something might be wrong, could be the boost/buck converter, could be the pot.
Best power supply have i ever seen) like!
I would like to have AC not only DC, do you have any suggestions?
A couple of questions. Why solder multiple 12v cables to the input of the converter? Why not just one 12v cable? Is it just for redundancy? Also, would you pick the the highest voltage output from the pc power supply or would it be better to pick the highest amp output on the pc supply. Last question, what is the middle potentiometer on the buck boost used for ? if the other two are used for voltage and ampage adjustment. If anyone could help me with this. It would be much appreciated!
12/24 V, 10A LED Switchmode Powersupply with an MingHe D3806, a Fan for bigger loads and thick wire + Case
Heu bro. I want to buy a step-up and a step-down converter. They should output the same voltage ranges?
The step-down converter output from 1.3 to 35 Volts and the step-up converter from 5-24volts.
May I ask what is the make & model number of your breadboard