@erik61801 the PC Power Supply I got has the 12v 1 and 12v 2. I hope I don't have to use the 12v for the dummy-load thing, if I do am fucked. still, am gonna try either a lightbulb or the 10w 10ohm resistor I already got whit the 5v red wires. I will also try two 10k ohm resistors for the LED's. thank you and JumperOneTV = D
at 00:39 you say negative 12V. How can you have negative 12V? I'm new to electronics and stumbled across this video and never heard of have a negative voltage.
@DavidLawton93 You should know that ground - it's a _virtual_ point. It's negative 12V _in relation to GND_. So, voltage between +12V and -12V would be 24V. Imagine these voltages as a line, with GND in the middle.
I have bought an 800w dual 12v rail @ 28a per rail PSU and am only concerned with the 12v outputs for the use of a 400w lipo battery charger. The question that I have is, can I combine the rails inside the case before soldering them to the binding posts? If so will it produce 336wx2=672w or am I limited to 336w on each rail? I really appreciated your video and thanks for the response before hand! Keep up the great work!
i dont really understand your series diagram. what wire is the neutral and hot?? and what do i do with 3.3v and 5v wires inn this situation? explanation was really vague and fast. So if you could clear it up for me id really appreciate it! Thanks!
I have a problem , when i connect green to black and give dummy load on red +5 to black ground nothing happens, but when I shut it down it gives me some high noise going down , what is that?
@JumperOneTV Fantastic video. Not a project i've done before and it's been 10 years since the last time I did electronics seriously. I do have a question for you as a math check: I've got a newer 500w model, so i've connected a dummy load across one of the 12v outputs (2x10 ohm 5W power resistors in series). The first resistor gets wicked hot, enough to smoke, so i checked my match and 12v/20 ohms = 0.6A and 0.6A x 12v = 7.2W.
@RunawayRadiostar I'm confused. Since there is 2x5W=10W of heat dissipation between two resistors, is the first attempting to dissipate all the heat by itself?
my amp is using 10A on it's max and my psu gives out 16A on 12V and it works fine :) The psu doesn't heat at all and i thik its made somwere in 2005-2006 and it is 350W so it works ;)
@goshobul Switch mode power supplies in general needs to have some output load in order to have stable output or to work at all. If you only need to power car stereo (or whatever else), you can try not to use any dummy load at all. If your psu is pretty old (older standard), you might need to add any dummy load (12V lightbulb) to 5V rail. Anyways, try and see if it works with only your stereo connected.
If a have a 12va 18A and a 12vb 18A can I put them together and have 12v 36 rail? Or do I need to separate them then I just connect the other ones like normal
Hey Phil! Świetny film! You inspired and motivated me to make my own PSU form old ATX ;-)
My modifications: I've put switch only for POWER_ON wire, mains switch on the back of the box works fine for me, green LED is connected to POWER_GOOD signal and I've mounted dummy load on heat sinks. I wonder if it is good idea to provide only one ground wire to dummy load.. I mean in terms of current (approx. 1A) flowing through that wire.
Just a cautionary message for the younger guys & gals, and beginners: the ATX power supply units (PSUs) *can be* very noisy, electrically. Whether this will be a problem depends on the application. High-speed digital circuits without (adequate) filtering and/or shielding are the most vulnerable, and the source of the noise can be a headache when troubleshooting communication problems.
That said, this method is perfectly fine for low-speed, noise-tolerant applications. So don't worry much. :)
@SigEpBlue Yes this is a good point. I think more importantly it might be worth mentioning that these PSU's really shouldn't be powered up without a load across them as it may result in damage. Dummy loads can be easily made using a bulb.
@petermines Very true, yes; some have used a 10Ω load between +5V and GND (500mA load), but that might be overkill. I'd suggest experimentation with various values of bulbs or power resistors, and 'dialing it in' that way.
Interestingly, some PSUs become audibly noisy with little to no load, because the circuitry switching speed slows down to sonic frequencies to compensate. This 'squeal' is common to hear on older PCs when shut off, i.e. no load, almost like flyback transformer noise. 8)
@SigEpBlue lol! ... we'll never win even with SM psu's. I remember in my apprenticeship days 41 years ago having to melt sealing wax on line stage coils to stop the "chatter"
Thanks for the tutorial! I tried to convert my power supply but I have a little problem. My green light turns on but I only get power from the outlets for a few seconds after I flick the power on switch, then no more power. Also I used two 100 ohm resistors in series for the dummy load, since I couldn't find any better. Could this be my problem?
@MrFlyingFishys you can use it to power any circuit that needs 3.3, 5, 12 or 24VDC and appropriate current requirements. (earth ground isolation is another thing to care about)
@MrFlyingFishys you can use it to power any circuit that needs 3.3, 5, 12 or 24VDC and appropriate current requirements. (earth ground isolation is another thing to care about)
@JumperOneTV can you tell me how to limit current on demand? for example i have a curcuit that i want to get 300ma of current, how do i limit the current from 2 amps with a pot resistor. would you be able to demonstrate that. because i am making a homemade powersupply and i am using an lm317t to regulate to voltage as i want, so i want the same thing with current. please help
@deagle94 Current limiting is a bit trickier than voltage regulation. Usually a 'sense' resistor is used in the current path, on the order of a few milliohms in value. Then another device, e.g. an op-amp, is used to measure/monitor the voltage drop across that resistor. What happens once you reach X voltage drop will depend upon your design.
To the point, you cannot set a current limit with a potentiometer alone. See youtube.com/watch?v=CIGjActDeoM for a great explanation!
@DanFrederiksen there's a lot of theory needs to be explained. maybe I will do video on that after explaining how SMPSs work. but most likely it'll create more questions, than answers.
Great video tutorial. I've got spare PSU lying around so I think I'll make use of it later on by doing this project. Thanks for the excellent tutorial.
by the way..... I have a question(about a problem i have) I have a 36-48v electric wheel(MagicPie) and i want to have a12volt battery with a dc-dc converter to 36 volt. You have any advice/circuit in your mind ? I was also wondering if that would burn the electronics of the wheel or not. Thanx mate.
Great channel and great blog. Did you bought cola ? i saw you run out from it in an other video.
I liked this video and i immidiately went to my stuff and i found an old atx power supply. Im gathering the stuff needed and in the weekend im going further(box is open, cables are cut, and sepperated.) I need to do the connections and start putting in together. Thanx for the very nice video, schematics, parts list, pcb.
@ryanjobse: Try it out first with a "non-manipulated" computer power supply. Some computer power supplies have a habit of turning off at large current changes. To get around this, you must find and deactivate the protection circuit. But be careful! The power supply is no longer "fully" protected! Any errors, whether inside the power supply or on its outputs "can" inevitably result in its destruction, and under some circumstances lead to fire.
I cant get more that a few amps out of my 12v rail when I add the dummy load of a 10ohm 25w resistor. It says it supplies a lot more that they though. It just shuts down without the load. Any suggestions?
@Evanator22742: How old is your computer power supply? Is among the many wires, a green here? This is needed to turn on the power supply. Since you can connect a small switch. The wire must be connected to ground to turn on the power supply.
There are also computer power supplies, which need a certain base load to work. I also have one of these. It shuts off for safety, so it is not destroyed by high running itself.
@Evanator22742: A 10 ohm resistor to 12V increases to only 1.2 amps and 14.4 watts. Computer power supplies are High-frequency switching power supplies. Unfortunately I do not know how they behave in different types of loads. I mean, capacitive, inductive or resistive.
What happens when you connect a 12V halogen bulb with 20 or 50 watts on the power supply? Test it.
@Evanator22742: A 10 ohm resistor to 12V increases to only 1.2 amps and 14.4 watts. Computer power supplies are High-frequency switching power supplies. Unfortunately I do not know how they behave in different types of loads. I mean, capacitive, inductive or resistive.
What happens when you connect a 12V halogen bulb with 20 or 50 watts on the power supply? Test it.
hello, i did this build and it was fairly easy but supplies were hit and miss here. i got stuck with what I believe is a bad choice of power resisters. tried to get the ones you use, but radio shack had 5W only in 0.47ohm. this thing gets screaming hot after just a few seconds. what do I need to do. also I found out my old power supply was an AT PSU not an ATX PSU and it has differen cords for power switch and I noticed you didn't cover that, any imput would be appreciated thanks
@JumperOneTV thanks for the quick response, i found your sugestion quite helpfull. I was trying to avoid ordering parts online but the selections available in local stores is unacceptable. radioshack had only 4 types of power resistors and none were even close. they didnt even have normal binding posts :( thanks again and I like you videos, very well done
@JumperOneTV so I built another one again from an older AT psu but this one had the dummy load built in and a few other perks like a nice filter on the ac in. works ok for the electro chem experiments I am doing. thanks for the info
Great Video very informative. Couple of questions - if you have a mains power on switch why do you need the low current switch as well when you can short the green on wire permanently? I've ordered an iluminated mains switch so i'll know its on without all the leds and resistors -am i missing something.
Any reason why you cant put a variable resistor on one of the 12v lines?
I'd like 9v so ive ordered a 9 volt regulator will it work to reduce 12volt to 9?
@SuperMadpom Low current puts PSU in standby mode, and back again. It's not necessary to put it there, but it's much easier to frequently flick a small switch instead of big one, and also each time when you use the mains switch - input caps are charging creating a short for a small period of time.
If PSU would fail, you'll know it right away. PSU has overcurrent protection - it shuts down when overcurrent occurs. With an LED you'll know about this right away.
@MrMuseh For bench power supply you don't need to use power_good wire at all. You can completely remove that wire.
And for resistors - first try to run PSU without resistors and without output load at all, then measure voltage (5V, 12V), after that connect one (then both) resistor and measure voltage again. If voltage almost doesn't change, then you don't need resistors, if it does, then put resistors there. Also, if it doesn't start up without resistors - then you need to put them.
@MrMuseh I didn't get it, so it is just a couple of years old? If so, try to connect both resistors in series and then connect them to GND and 12V rail.
@JumperOneTV i tried connecting the resistor in series via 12v rail.. it doesn't start... how ever.. i tried it with three 5watt 8.2 ohm in paralel with 5v rail...i have to switch it on and off a few time or wait for a few second before turning it on, then it works.. do i need to add more resistor or it just the capasitor need to be charged first?
@MrMuseh You can try to add another resistor, but I got to say, that you have a weird power supply :) Usually it's enough to put only one 10 ohms resistor on 5V rail. (maybe even less), but it's strange, that your PSU needs 3 8.2 ohms resistors. It's about 9 watts dissipated in heat. Try to measure voltage with 3 resistors load, maybe it's far from 5V? Anyways, it's strange )
@MrMuseh to +5V in parallel. (but with other power supply, try first without resistors at all, and then add some). Experimenting - it's a good way to know how things work :)
@ARGYPILATUS If you mean, connect all the 12V rails on the first PSU, then connect all the 12V rails on the other one, and then connect two power supplies in series to get 24V, then yes, you can. But don't forget about earth ground problem, or you'll short out one of the power supplies. In this video I explained, what this problem is all about. Plus, it could be dangerous(could be) because you disconnecting earth ground terminal from one of the power supplies.
The new generation ATX need also resistors at lower voltage 5v output?and how much?Do i loose 30% current?Thank you for your help and your answers!!!!
@ARGYPILATUS Yes, you would have more loading capability! 12V1, 12V2, etc. - is not separate transformer taps, but just overcurrent protection on each of those channels.
Q1) I hooked a 12Ohm to the 12v to ground (12A) and it dropped from 12 to 8V.
Q2) Is the drop because I am not using dummy load resister?
Q3) What is the resister that needs to go in between 3.3 and sense? Is this the reason for the drop?
Q4) When I hook up dummy resister it gets really hot fast. (reason I didnt use it) Is there something else getting hot because I am not using Dummy load resister?
The Dummy Load to 5v kills it. to 12v Seems to be fine. But it still drops to 8v with 1 ohm test
@FullWaveElectronics Voltage drop on 12V rail might be because of cross-regulation (google for it) - yes, it might be because you don't have a dummy load resistor on 5V rail. Or you might have a pretty bad power supply.
There is no resistor between 3.3V and 3.3V sense!
Of course resistor will get hot! And that's why you need an appropriate power resistor for that task. Well it's Ohm's law..
No I do NOT have a resister between 3.3v and 3.3 sense. In your vid it looks like you have one at 4:10 . I did however get this thing to start up without the Dummy and without the connecting 3.3 and sense. But I noticed a voltage drop proportional to current speed.
I went ahead and connected 3.3 and sense and I do not notice anything different.
All voltages are correct with no load.
I read about and watched a video on cross-regulation... it is so far over my head i just learned ohms law)
@FullWaveElectronics this power supply was brand new, it may be bad, but I doubt it. Should Cross Regulation be a problem with computer power supply? Wouldn't a "regulated" power supply prevent this?
@FullWaveElectronics In video I said, that wires represent a small resistance. So, there's no actual resistor there. It's just the wires have their own resistance (very small value).
The computer psu - is already regulated power supply! It means, that it's output voltage should not depend too much from output load or input voltage.
By the "bad" I meant that you could have some cheap no-name psu. And usually those cheap power supplies can't provide as much current as claimed on a sticker.
@JumperOneTV Coolmax V-500 and coudn't find the date anywhere. I know it was made for Pentium 4 and Athlons.
BTW there was never a wire in the 3.3 sense. So I had to find that spot on the circuit board and solder one in. So it was manufactured without a sense wire. Weird huh?
I will make another one if I have too... I do not want voltage drop.. it messes up the math for me, I am very new to electronics.
Video muito bom!Tambem fiz uma modificação numa fonte ATX,para alimentar um Radio CB,que funciona a 100%. Porem substitui as resistencias por uma lampada de carro traseira de 2 polos ligada em +5V e 0V.
A litle suggestion: when soldering these wires from the PSU, don't do that like you do in video, the solder may drip onto the PCB of the PSU and short out something, without you even noticing it. I learned it the hard way..
hi great video. I was wondering if you can tell me how to connect 2 ATX PSU together. i have a car amplifier that i am using in my room and the psu i am using to power it, is not supplying enough amperage, but if i connect 2 ATX PSU then it can be supplied with enough power. and yes i know i can use inverters and other devices or buy a more powerful PSU, but i want to use the Computer PSUs that i have, any help will be appreciated.
Hello my friend, i would like to ask if necessary to use the 2 withe 2 white big resistance in 5 volt, because my psu work nice when connect the gren with balck cable.
ur gay
itslife56 21 hours ago
This has been flagged as spam show
if i connect +5v and -12v and get 17v
will the max amp be 0.8A or 12A (+5v=12A, -12v=0.8A)
Mahejma 2 days ago
Comment removed
Mahejma 2 days ago
I got me a 10w 100ohm resistor but I was told to go a little higher than that. what is your opinion concerning this ???
LocoLibreisI 2 days ago
@LocoLibreisI Just try and see if it works for your PSU. If it doesn't - try lower resistance value.
JumperOneTV 2 days ago
@LocoLibreisI Just use a lightbulb, like a brake light for a car, works on either 12 or 5. Its what Ive done and is cheap and works
erik61801 21 hours ago
@erik61801 the PC Power Supply I got has the 12v 1 and 12v 2. I hope I don't have to use the 12v for the dummy-load thing, if I do am fucked. still, am gonna try either a lightbulb or the 10w 10ohm resistor I already got whit the 5v red wires. I will also try two 10k ohm resistors for the LED's. thank you and JumperOneTV = D
LocoLibreisI 10 hours ago
@LocoLibreisI No sir you dont have to dummy the 12v side. You just need some sort of load on the +5v side to regulate properly. Good luck
erik61801 7 hours ago
Comment removed
LocoLibreisI 2 days ago
at 00:39 you say negative 12V. How can you have negative 12V? I'm new to electronics and stumbled across this video and never heard of have a negative voltage.
DavidLawton93 3 days ago
@DavidLawton93 You should know that ground - it's a _virtual_ point. It's negative 12V _in relation to GND_. So, voltage between +12V and -12V would be 24V. Imagine these voltages as a line, with GND in the middle.
JumperOneTV 3 days ago
@JumperOneTV Ok and is there a difference between +12V and -12V? Thanks for replying. :)
DavidLawton93 3 days ago
@DavidLawton93 In case of ATX PSU - negative 12V can supply only about 1 amp.
JumperOneTV 2 days ago
am thinking about building one whit a computer power supply that got for about 10 euros.
250w ATX PS
AC input 115 / 230V - 60/50Hz
DC out **************** +3.3 , +5v , +12 , -12v , +5VSB
Max Combine Wattage 15A , 14A , 15A , 0.6A , 2A
is this good enough to build a your project whit mr, JumperOneTV sir ???
LocoLibreisI 3 days ago
@LocoLibreisI Pretty much any psu will be ok! And be careful with mains wiring. Don't forget, that it's a high voltage!
JumperOneTV 3 days ago
Excellent video.
tommeasor 3 days ago
I have bought an 800w dual 12v rail @ 28a per rail PSU and am only concerned with the 12v outputs for the use of a 400w lipo battery charger. The question that I have is, can I combine the rails inside the case before soldering them to the binding posts? If so will it produce 336wx2=672w or am I limited to 336w on each rail? I really appreciated your video and thanks for the response before hand! Keep up the great work!
MrSpeedobsessive 4 days ago
i dont really understand your series diagram. what wire is the neutral and hot?? and what do i do with 3.3v and 5v wires inn this situation? explanation was really vague and fast. So if you could clear it up for me id really appreciate it! Thanks!
kade12345678910 4 days ago
where did u connect the power good wire to?
JJewlz 5 days ago
hey how did you connect the LED's...i understand that you connected it to a current limiting resistor but where did u connect the negative lead to?
JJewlz 5 days ago
Damn, that thing looks pretty damn professional and clean. The one sitting on my desk is just jerry rigged with some spare cables and hot glue ahah
foil666 1 week ago
Hello ive make mine right now watching your vid. Is there a way to make it adjustable? Cheers.
Tuningology 1 week ago
@Tuningology Unfortunately, there's no easy way to make it adjustable. And by easy I mean - without knowledge how SMPS works.
JumperOneTV 1 week ago
what a waste of heatshrink! You know most people consider 20-30mm ample
dillzio 1 week ago
@dillzio what a waste of comment
JumperOneTV 1 week ago 5
@JumperOneTV did you learn to speak English from watching Sesame Street? You talk like Elmo
dillzio 1 week ago
@dillzio how'd you know, sweetie? :-*
JumperOneTV 1 week ago
I have a problem , when i connect green to black and give dummy load on red +5 to black ground nothing happens, but when I shut it down it gives me some high noise going down , what is that?
DJReastro 2 weeks ago
great job, great instruction, nice camera work. fantastic!
granaleo1 2 weeks ago
This has been flagged as spam show
@JumperOneTV Fantastic video. Not a project i've done before and it's been 10 years since the last time I did electronics seriously. I do have a question for you as a math check: I've got a newer 500w model, so i've connected a dummy load across one of the 12v outputs (2x10 ohm 5W power resistors in series). The first resistor gets wicked hot, enough to smoke, so i checked my match and 12v/20 ohms = 0.6A and 0.6A x 12v = 7.2W.
RunawayRadiostar 2 weeks ago
Comment removed
RunawayRadiostar 2 weeks ago in playlist Audio and Electronics
This has been flagged as spam show
@RunawayRadiostar I'm confused. Since there is 2x5W=10W of heat dissipation between two resistors, is the first attempting to dissipate all the heat by itself?
RunawayRadiostar 2 weeks ago in playlist Audio and Electronics
Comment removed
RunawayRadiostar 2 weeks ago
Comment removed
RunawayRadiostar 2 weeks ago
Pretty good video well done project very professional
ronurban13 2 weeks ago
didnt you say it needed 22 ohms? 2-11 ohm resistors in parallel is only 5.5ohms total.
Warndog09 2 weeks ago
@Warndog09 no you didnt, you said it needed 5, sorry haha
Warndog09 2 weeks ago
@Warndog09 :)
JumperOneTV 2 weeks ago
nice
helifors 3 weeks ago
my amp is using 10A on it's max and my psu gives out 16A on 12V and it works fine :) The psu doesn't heat at all and i thik its made somwere in 2005-2006 and it is 350W so it works ;)
goshobul 3 weeks ago
@goshobul cool! music it's always good :)
JumperOneTV 3 weeks ago
i don't have a dummy load and i use it only for 12 volts to power up my amp! Do i realy need a dummy load? And if yes why, and if no why?
goshobul 3 weeks ago in playlist psu
@goshobul Switch mode power supplies in general needs to have some output load in order to have stable output or to work at all. If you only need to power car stereo (or whatever else), you can try not to use any dummy load at all. If your psu is pretty old (older standard), you might need to add any dummy load (12V lightbulb) to 5V rail. Anyways, try and see if it works with only your stereo connected.
JumperOneTV 3 weeks ago
A great tutorial. My 10W 5ohm resistor on the 5v rail as dummy load gets really hot. Is this normal?
legbaoz 1 month ago
@legbaoz Yep, that's normal! Currently you dissipating 5W of power in that 5 ohm resistor. P = V^2/R. You can't beat the Ohms Law :))
JumperOneTV 1 month ago
@JumperOneTV Cheers for the reply. I didn't think 5W would be so toasty.
legbaoz 1 month ago
could 11.6 ohms 10 watts work? or 51 ohms 5 watts?
DactaDork 1 month ago in playlist Science tools
@DactaDork it differs from psu to psu, so just try and see which one works for you.
JumperOneTV 1 month ago
@JumperOneTV i am using an older supply, a NMB model MJPC-270A1, a 268.9W supply with most of the current on 5V.
DactaDork 1 month ago
@DactaDork also, i have 4 5W resistors to use in total: 0.22, 0.22, 18, and 33.
DactaDork 1 month ago
This has been flagged as spam show
@JumperOneTV i have 4 5W resistors to use in total: 0.22, 0.22, 18, and 33.
DactaDork 1 month ago
I'm trying to bump up voltage.
Having a problem with this common ground.
Can you explain or better yet, do a vid on how?
olddawgsrule 1 month ago
How much are lab power supply going for??
LocoLibreisI 1 month ago
If a have a 12va 18A and a 12vb 18A can I put them together and have 12v 36 rail? Or do I need to separate them then I just connect the other ones like normal
kevonmalon 1 month ago
@kevonmalon never mind i got it working thanks for the vid
kevonmalon 1 month ago
why so much heat shrink ,,to bad i didnt have stock
otisculver1 1 month ago
This has been flagged as spam show
i dont have a brown wire the +3.3sense does that matter
Daniel3200000 1 month ago
Hey Phil! Świetny film! You inspired and motivated me to make my own PSU form old ATX ;-)
My modifications: I've put switch only for POWER_ON wire, mains switch on the back of the box works fine for me, green LED is connected to POWER_GOOD signal and I've mounted dummy load on heat sinks. I wonder if it is good idea to provide only one ground wire to dummy load.. I mean in terms of current (approx. 1A) flowing through that wire.
Anyway clever and tidy construction.
Greetings from Poland!
jimarcin 1 month ago
for 12 volt can i use 10W47ohm
or for old atx 5 volt can i use 5w10ohm
Daniel3200000 1 month ago
@Daniel3200000 yes, you can try to use any of those.
JumperOneTV 1 month ago
i dont have a brown wire the +3.3sense does that matter
Daniel3200000 1 month ago
Is the host Polish by chance?
marcus3379 1 month ago
@marcus3379 Close enough. I'm Ukrainian.
JumperOneTV 1 month ago
Just a cautionary message for the younger guys & gals, and beginners: the ATX power supply units (PSUs) *can be* very noisy, electrically. Whether this will be a problem depends on the application. High-speed digital circuits without (adequate) filtering and/or shielding are the most vulnerable, and the source of the noise can be a headache when troubleshooting communication problems.
That said, this method is perfectly fine for low-speed, noise-tolerant applications. So don't worry much. :)
SigEpBlue 1 month ago in playlist Favorite videos
@SigEpBlue Yes this is a good point. I think more importantly it might be worth mentioning that these PSU's really shouldn't be powered up without a load across them as it may result in damage. Dummy loads can be easily made using a bulb.
petermines 1 month ago
@petermines Very true, yes; some have used a 10Ω load between +5V and GND (500mA load), but that might be overkill. I'd suggest experimentation with various values of bulbs or power resistors, and 'dialing it in' that way.
Interestingly, some PSUs become audibly noisy with little to no load, because the circuitry switching speed slows down to sonic frequencies to compensate. This 'squeal' is common to hear on older PCs when shut off, i.e. no load, almost like flyback transformer noise. 8)
SigEpBlue 1 month ago
@SigEpBlue lol! ... we'll never win even with SM psu's. I remember in my apprenticeship days 41 years ago having to melt sealing wax on line stage coils to stop the "chatter"
petermines 1 month ago
Thanks for the tutorial! I tried to convert my power supply but I have a little problem. My green light turns on but I only get power from the outlets for a few seconds after I flick the power on switch, then no more power. Also I used two 100 ohm resistors in series for the dummy load, since I couldn't find any better. Could this be my problem?
Thanks!!
roach230 1 month ago
@roach230 Nevermind, I figured it out. It seems as though the 3.3V sense wire (brown) needs to be bundled with the 3.3V orange wires for it to work
roach230 1 month ago
And what are you using to shrink your tubing?
MrFlyingFishys 1 month ago
@MrFlyingFishys smd rework station heat gun.
JumperOneTV 1 month ago
what is this sort of power supply used for?
MrFlyingFishys 1 month ago
@MrFlyingFishys you can use it to power any circuit that needs 3.3, 5, 12 or 24VDC and appropriate current requirements. (earth ground isolation is another thing to care about)
JumperOneTV 1 month ago
@MrFlyingFishys you can use it to power any circuit that needs 3.3, 5, 12 or 24VDC and appropriate current requirements. (earth ground isolation is another thing to care about)
JumperOneTV 1 month ago
@JumperOneTV can you tell me how to limit current on demand? for example i have a curcuit that i want to get 300ma of current, how do i limit the current from 2 amps with a pot resistor. would you be able to demonstrate that. because i am making a homemade powersupply and i am using an lm317t to regulate to voltage as i want, so i want the same thing with current. please help
deagle94 1 month ago
Comment removed
SigEpBlue 1 month ago in playlist Favorite videos
This has been flagged as spam show
@deagle94 Current limiting is a bit trickier than voltage regulation. Usually a 'sense' resistor is used in the current path, on the order of a few milliohms in value. Then another device, e.g. an op-amp, is used to measure/monitor the voltage drop across that resistor. What happens once you reach X voltage drop will depend upon your design.
To the point, you cannot set a current limit with a potentiometer alone. See youtube.com/watch?v=CIGjActDeoM for a great explanation!
SigEpBlue 1 month ago in playlist Favorite videos
Hi , nice video , i am working this right now . And i do some tests , and it gives me 9.38 V instead of 12v ! Please help me what to do !! Thanks
lselectronicsGR 1 month ago
@lselectronicsGR I fix it up , but it gives me 11.38 now !!
lselectronicsGR 1 month ago
@lselectronicsGR 11.38 is fine in most cases. it largely depends on output load. google for "power supply cross regulation".
JumperOneTV 1 month ago
why use so much heatshrink tubing!!!??? such a waste!
plavins1 1 month ago
@plavins1 Because it looks good! )))
JumperOneTV 1 month ago
it needs to be variable too
DanFrederiksen 2 months ago
@DanFrederiksen It's not to hard for me to do, but it would very hard to explain to everyone, who doesn't know in detail how SMPSs work.
JumperOneTV 2 months ago
@JumperOneTV why would it be hard.. give it a try
DanFrederiksen 2 months ago
@DanFrederiksen there's a lot of theory needs to be explained. maybe I will do video on that after explaining how SMPSs work. but most likely it'll create more questions, than answers.
JumperOneTV 2 months ago
Great video tutorial. I've got spare PSU lying around so I think I'll make use of it later on by doing this project. Thanks for the excellent tutorial.
orbiter8 2 months ago
i have a question what happens if we mesure the voltage betwin any positive two phase
P1001AT2 2 months ago
Nice :)
NikyRipy 2 months ago
finally, i can used some thing like this to power a high power laser
canoblas 2 months ago
Nice work !!!
ExPlOdInGmAn1980 2 months ago
This is the best video I have ever seen on YouTube. Well done!!! If you were doing this as a part of a school project I would have given you an A.
PSUPhysicsStudent 2 months ago
what is the use of -5v and -12v?
EvendimataE 2 months ago
by the way..... I have a question(about a problem i have) I have a 36-48v electric wheel(MagicPie) and i want to have a12volt battery with a dc-dc converter to 36 volt. You have any advice/circuit in your mind ? I was also wondering if that would burn the electronics of the wheel or not. Thanx mate.
EllinonEnosis 2 months ago
Great channel and great blog. Did you bought cola ? i saw you run out from it in an other video.
I liked this video and i immidiately went to my stuff and i found an old atx power supply. Im gathering the stuff needed and in the weekend im going further(box is open, cables are cut, and sepperated.) I need to do the connections and start putting in together. Thanx for the very nice video, schematics, parts list, pcb.
EllinonEnosis 2 months ago
do you need to have a dummy if it will be connected to a car amp?
ryanjobse 2 months ago
@ryanjobse in your case, you just have to try.
JumperOneTV 2 months ago
@ryanjobse: Try it out first with a "non-manipulated" computer power supply. Some computer power supplies have a habit of turning off at large current changes. To get around this, you must find and deactivate the protection circuit. But be careful! The power supply is no longer "fully" protected! Any errors, whether inside the power supply or on its outputs "can" inevitably result in its destruction, and under some circumstances lead to fire.
djblackarrow 2 months ago
can i charge a 12v battery by these atx power supply
and can you right the names of the tools you have use it
thank you
am from syria
mazenmukdad 2 months ago
I cant get more that a few amps out of my 12v rail when I add the dummy load of a 10ohm 25w resistor. It says it supplies a lot more that they though. It just shuts down without the load. Any suggestions?
Evanator22742 2 months ago
@Evanator22742 It might be due to the cross-regulation problems. (google for it)
Try to put about 1A load on 5V rail, and put 20 ohms resistor on 12V rail, instead of 10 ohms.
JumperOneTV 2 months ago
@Evanator22742: How old is your computer power supply? Is among the many wires, a green here? This is needed to turn on the power supply. Since you can connect a small switch. The wire must be connected to ground to turn on the power supply.
There are also computer power supplies, which need a certain base load to work. I also have one of these. It shuts off for safety, so it is not destroyed by high running itself.
djblackarrow 2 months ago
@Evanator22742: A 10 ohm resistor to 12V increases to only 1.2 amps and 14.4 watts. Computer power supplies are High-frequency switching power supplies. Unfortunately I do not know how they behave in different types of loads. I mean, capacitive, inductive or resistive.
What happens when you connect a 12V halogen bulb with 20 or 50 watts on the power supply? Test it.
djblackarrow 2 months ago
This has been flagged as spam show
@Evanator22742: A 10 ohm resistor to 12V increases to only 1.2 amps and 14.4 watts. Computer power supplies are High-frequency switching power supplies. Unfortunately I do not know how they behave in different types of loads. I mean, capacitive, inductive or resistive.
What happens when you connect a 12V halogen bulb with 20 or 50 watts on the power supply? Test it.
djblackarrow 2 months ago
I just wish I had the skills!
TechnoZombie 2 months ago
Hey dude you must also show how to add led with resistor and which wire should go to power resistor
Narutopuneet 2 months ago
Jij bent nederlands :)
kan jij me meer tips geven ??
randybolhuis1 2 months ago
One of the most coolest and helpfull videos in you(full of crapy videos)tube.
EllinonEnosis 2 months ago
What value resister do we use in line with the led's. Don
demuruphy1 2 months ago
hello, i did this build and it was fairly easy but supplies were hit and miss here. i got stuck with what I believe is a bad choice of power resisters. tried to get the ones you use, but radio shack had 5W only in 0.47ohm. this thing gets screaming hot after just a few seconds. what do I need to do. also I found out my old power supply was an AT PSU not an ATX PSU and it has differen cords for power switch and I noticed you didn't cover that, any imput would be appreciated thanks
Demonchld666 2 months ago
@Demonchld666 1. Ohms law. P = (V^2)/R.
2. DigiKey dot com
3. Wikipedia AT power supply
JumperOneTV 2 months ago
@JumperOneTV thanks for the quick response, i found your sugestion quite helpfull. I was trying to avoid ordering parts online but the selections available in local stores is unacceptable. radioshack had only 4 types of power resistors and none were even close. they didnt even have normal binding posts :( thanks again and I like you videos, very well done
Demonchld666 2 months ago
@JumperOneTV so I built another one again from an older AT psu but this one had the dummy load built in and a few other perks like a nice filter on the ac in. works ok for the electro chem experiments I am doing. thanks for the info
demnlordd666 2 months ago
Great Video very informative. Couple of questions - if you have a mains power on switch why do you need the low current switch as well when you can short the green on wire permanently? I've ordered an iluminated mains switch so i'll know its on without all the leds and resistors -am i missing something.
Any reason why you cant put a variable resistor on one of the 12v lines?
I'd like 9v so ive ordered a 9 volt regulator will it work to reduce 12volt to 9?
just waiting for parts now THKS
SuperMadpom 2 months ago
@SuperMadpom Low current puts PSU in standby mode, and back again. It's not necessary to put it there, but it's much easier to frequently flick a small switch instead of big one, and also each time when you use the mains switch - input caps are charging creating a short for a small period of time.
If PSU would fail, you'll know it right away. PSU has overcurrent protection - it shuts down when overcurrent occurs. With an LED you'll know about this right away.
V. reg. will work.
JumperOneTV 2 months ago
Dear Phil here is my power sypply build.Thank you for your help!!!
ARGYPILATUS 2 months ago
Drilling into an undissected devise? The iron turnings can fall on PCB => bäääm
Prometreus 3 months ago
@Prometreus Not again! ))) (see the previous comments)
JumperOneTV 3 months ago
@JumperOneTV Ok I see :)
Prometreus 3 months ago
Awesome job! I especially like how you reused the old wire hole for the switch, worked out nicely!
joesmoe71 3 months ago
excuse me, where do i need to connect the grey [power good] wire?
and are 2x 5watt 8.2 ohm is enough for the resistor?
thanks~ :)
MrMuseh 3 months ago
@MrMuseh For bench power supply you don't need to use power_good wire at all. You can completely remove that wire.
And for resistors - first try to run PSU without resistors and without output load at all, then measure voltage (5V, 12V), after that connect one (then both) resistor and measure voltage again. If voltage almost doesn't change, then you don't need resistors, if it does, then put resistors there. Also, if it doesn't start up without resistors - then you need to put them.
JumperOneTV 3 months ago
@JumperOneTV ok~ i tried with the resistor~ and the PSU doesn't start~ then i add another resistor~ it start for a few second then its off again..
MrMuseh 3 months ago
@MrMuseh How old your psu is? And where you connect the resistors(5V or 12V rail)?
JumperOneTV 3 months ago
@JumperOneTV not really that old~ a few year back then~ i connect it to the 5volt rail~ it has the white wire~
MrMuseh 3 months ago
@MrMuseh I didn't get it, so it is just a couple of years old? If so, try to connect both resistors in series and then connect them to GND and 12V rail.
JumperOneTV 3 months ago
@JumperOneTV thanks~ i will try again tomorrow~ will ask u again if its still doesn't work~ pardon me for my bad english~ i'm from Malaysia~ :)
MrMuseh 3 months ago
@MrMuseh Sure! And your english is OK! (but you might want to drop that "~" things) :)
JumperOneTV 3 months ago
@JumperOneTV i tried connecting the resistor in series via 12v rail.. it doesn't start... how ever.. i tried it with three 5watt 8.2 ohm in paralel with 5v rail...i have to switch it on and off a few time or wait for a few second before turning it on, then it works.. do i need to add more resistor or it just the capasitor need to be charged first?
MrMuseh 3 months ago
@MrMuseh You can try to add another resistor, but I got to say, that you have a weird power supply :) Usually it's enough to put only one 10 ohms resistor on 5V rail. (maybe even less), but it's strange, that your PSU needs 3 8.2 ohms resistors. It's about 9 watts dissipated in heat. Try to measure voltage with 3 resistors load, maybe it's far from 5V? Anyways, it's strange )
JumperOneTV 3 months ago
@JumperOneTV i tried measuring the voltage. it's exactly 5volt on the 5v rail, 12volt on the 12 volt rail..
another weird thing is, it wont start again, just about 3 second and it cut off..
MrMuseh 3 months ago
@MrMuseh yeah, it's strange.. I guess, you would have to find another old power supply :( or at least try the same thing with another one.
JumperOneTV 3 months ago
@JumperOneTV wait.. i have to conect it parelelly or in series?[the resistor]..
MrMuseh 3 months ago
@MrMuseh to +5V in parallel. (but with other power supply, try first without resistors at all, and then add some). Experimenting - it's a good way to know how things work :)
JumperOneTV 3 months ago
Phill can i conect two NEW Generation Atx in series for 24V and also parallel each one?12v1parallel12v2 in series with 12v1parallel 12v2=24v?
Thanks
ARGYPILATUS 3 months ago
@ARGYPILATUS If you mean, connect all the 12V rails on the first PSU, then connect all the 12V rails on the other one, and then connect two power supplies in series to get 24V, then yes, you can. But don't forget about earth ground problem, or you'll short out one of the power supplies. In this video I explained, what this problem is all about. Plus, it could be dangerous(could be) because you disconnecting earth ground terminal from one of the power supplies.
JumperOneTV 3 months ago
Comment removed
ARGYPILATUS 3 months ago
The new generation ATX need also resistors at lower voltage 5v output?and how much?Do i loose 30% current?Thank you for your help and your answers!!!!
ARGYPILATUS 3 months ago
@ARGYPILATUS No, the new generation of ATX PSUs doesn't need additional load on 5V. Why do you think, that you'll loose 30% current? You don't.
JumperOneTV 3 months ago
Hallo Phil can i ask you if i can take more ambere if i have the new ATX's and conect 12V1 parallel with 12V2.
20A and 20A TOTAL 40A?
ARGYPILATUS 3 months ago
@ARGYPILATUS Yes, you would have more loading capability! 12V1, 12V2, etc. - is not separate transformer taps, but just overcurrent protection on each of those channels.
JumperOneTV 3 months ago
can i use this to power my 12v R/C bump starter motor?
kabobek 3 months ago
@kabobek It depends how much current it draws.
JumperOneTV 3 months ago
yes this is the right way to drill holes and get a big bang at the end great job!
TheOffPowerZero 3 months ago
@TheOffPowerZero yep! )
JumperOneTV 3 months ago
Pretty useless if your doing low noise stuff.
Chryseus8086 3 months ago
@Chryseus8086 so is pie. but, people use that for eating.
chilleffect 3 months ago
@chilleffect LOL! Nice one! ))
JumperOneTV 3 months ago
nicely done.. I'm currently making one without the dummy load but it works...
CrimelabS 3 months ago
Is there a way to make this isolated? My scope ground is connected to the power supply indirectly through mains ground.
FullWaveElectronics 3 months ago
@FullWaveElectronics There is, but I don't recommend you to do that. It's not safe.
JumperOneTV 3 months ago
Q1) I hooked a 12Ohm to the 12v to ground (12A) and it dropped from 12 to 8V.
Q2) Is the drop because I am not using dummy load resister?
Q3) What is the resister that needs to go in between 3.3 and sense? Is this the reason for the drop?
Q4) When I hook up dummy resister it gets really hot fast. (reason I didnt use it) Is there something else getting hot because I am not using Dummy load resister?
The Dummy Load to 5v kills it. to 12v Seems to be fine. But it still drops to 8v with 1 ohm test
FullWaveElectronics 4 months ago
@FullWaveElectronics Voltage drop on 12V rail might be because of cross-regulation (google for it) - yes, it might be because you don't have a dummy load resistor on 5V rail. Or you might have a pretty bad power supply.
There is no resistor between 3.3V and 3.3V sense!
Of course resistor will get hot! And that's why you need an appropriate power resistor for that task. Well it's Ohm's law..
JumperOneTV 4 months ago
Comment removed
FullWaveElectronics 4 months ago
No I do NOT have a resister between 3.3v and 3.3 sense. In your vid it looks like you have one at 4:10 . I did however get this thing to start up without the Dummy and without the connecting 3.3 and sense. But I noticed a voltage drop proportional to current speed.
I went ahead and connected 3.3 and sense and I do not notice anything different.
All voltages are correct with no load.
I read about and watched a video on cross-regulation... it is so far over my head i just learned ohms law)
FullWaveElectronics 4 months ago
@FullWaveElectronics this power supply was brand new, it may be bad, but I doubt it. Should Cross Regulation be a problem with computer power supply? Wouldn't a "regulated" power supply prevent this?
FullWaveElectronics 4 months ago
@FullWaveElectronics In video I said, that wires represent a small resistance. So, there's no actual resistor there. It's just the wires have their own resistance (very small value).
The computer psu - is already regulated power supply! It means, that it's output voltage should not depend too much from output load or input voltage.
By the "bad" I meant that you could have some cheap no-name psu. And usually those cheap power supplies can't provide as much current as claimed on a sticker.
JumperOneTV 4 months ago
@FullWaveElectronics What is your power supply date of manufacture is?
JumperOneTV 4 months ago
@JumperOneTV Coolmax V-500 and coudn't find the date anywhere. I know it was made for Pentium 4 and Athlons.
BTW there was never a wire in the 3.3 sense. So I had to find that spot on the circuit board and solder one in. So it was manufactured without a sense wire. Weird huh?
I will make another one if I have too... I do not want voltage drop.. it messes up the math for me, I am very new to electronics.
FullWaveElectronics 4 months ago
Comment removed
FullWaveElectronics 4 months ago
Comment removed
FullWaveElectronics 4 months ago
Comment removed
FullWaveElectronics 4 months ago
Nicely done! Nice tools too.
MrDubje 4 months ago
How much load exactly does 5V line require? Could you put lets say two 5 volt fans instead of dummy load and remove 12V fan?
koktelici 4 months ago
@koktelici just try it and see if it works. maybe your psu doesn't even need any output load.
JumperOneTV 4 months ago
Very Very GOOD..congratulations u are fantastic !!:D
igor99480 4 months ago
Video muito bom!Tambem fiz uma modificação numa fonte ATX,para alimentar um Radio CB,que funciona a 100%. Porem substitui as resistencias por uma lampada de carro traseira de 2 polos ligada em +5V e 0V.
31mimo 4 months ago
A litle suggestion: when soldering these wires from the PSU, don't do that like you do in video, the solder may drip onto the PCB of the PSU and short out something, without you even noticing it. I learned it the hard way..
pinzponx 4 months ago
hi great video. I was wondering if you can tell me how to connect 2 ATX PSU together. i have a car amplifier that i am using in my room and the psu i am using to power it, is not supplying enough amperage, but if i connect 2 ATX PSU then it can be supplied with enough power. and yes i know i can use inverters and other devices or buy a more powerful PSU, but i want to use the Computer PSUs that i have, any help will be appreciated.
ahan153 4 months ago
Hello my friend, i would like to ask if necessary to use the 2 withe 2 white big resistance in 5 volt, because my psu work nice when connect the gren with balck cable.
thanks!!!
danetpro 4 months ago