Remove short-circuit protection from a psu.

Hi, i'm new here and i have a little problem. I want to make a soldering iron because mine is broken. I have a ATX PSU, but when i short circuit the 12v(16a) output the PSU shutdown. I want to remove the short-circuit protection  from my psu, how i do ? I'm begginer in the electronics, so please help me step by step. BTW, Sorry for my crappy english, i'm just a romanian guy :P

Posted by GFXMihnea 5 years ago


Need help Hooking Car Stereo up to PSU for inside home use.

I need help hooking this up.  I got the main idea of the player itself(as in what wires are for what)   but when it comes to the PSU i am so lost. SO MANY WIRES AND PINS!  i need help knowing what to cut, what to connect to what.  I have seen some instructions around here and online but i just cant seem to get it right.  Thanks  Oh keep in mind this psu has a on off switch.

Posted by valmont325 7 years ago


PSU Power Supply

I built a PSU bench power supply, but it isnt outputing the right voltages. It just out 5v for all lines(12v,5v). It has a purple wire that is said to be the stand-by, but the psu wont start unless it is connected to the 12v or 5v line. It also says that you have to have the brown sense wire attached to the 3v wire but this seems to do nothing. How can I make this thing output the right power(12v @ 22A, 5v @ 50A)?

Posted by tylerb 10 years ago


High current variable voltage from an atx psu

What would be the most simplistic way to draw up to 10a on an atx PSU using variable voltage controlled by a potentiometer? I've looked at a few diagrams using the LM317 but it is limited to 1.5a. The only other VVR I can find is the LM350 but is still limited to 3a. Any ideas? I was thinking of stacking an arrey of LM350s in parallel but this doesn't seem like a viable answer.

Posted by andrewlapham2010 1 year ago


Adjustable Voltage on PSU ATX

I have an old Rockford P450.4 amplifier that I salvaged an LM317T and LM337T from. It also had some two (2) potentiometers that I salvages as well. I have a 400W Coolamx PSU ATX that I turned into a bench supply. I have read that people have been using these two (2) IC's to maintain a constant voltage through variable adjustment. I have seen several tutorials on instructables, but that all lack clarity, instruction and do not provide enough detail. I could really use a good tutorial, but have failed to find one of great interest.

Posted by bprins 2 years ago


Voltage rail identification on LCD PCB

I am testing the DC rails coming off an LCD TV PSU so i can convert the unit to run off an ATX PSU. i have managed to find (labelled on the board) 12v, 12v, NC, GND, GND, GND, ?, ?  the last two aren't  labelled. the two pins (when tested to GND) are giving me -12v, could this be right? I'm guessing by this point ill just have to use the 12v rails, GND and -12v from the ATX to get this powered?  what else could those last two pins be? 

Posted by andrewlapham2010 1 year ago


Turning on an old Psu

Hey there, I got this old PSU, a Delta DPS-350EB-3 from an HP NetServer. I'm trying to make a lab power supply out of it, i just can't get it to power on. There's a blue wire bundled with a ground that when shorted will power the psu for a second then shut it back off.  I tried to put a load on the 5v & 12v with no success. Anyone got an idea? Thanks

Posted by wbzial 4 years ago


Turning On an old PSU - When all failed

Hey there ! I have this old psu that came from an HP NetServer, Delta DPS-350EB, an old AT form psu and i just can't get it to turn on manually. I have a Dark Blue wire bundled with a ground that's coming from a ''pwr ON'' labeled pin in the psu, when shorted the psu come alive for 2 seconds then shut back off. I tried putting a load (CD drive) on the 5v with no success. Tried shorting all the other cable (those that i know aren't 3v, 5v, 12v + or -) with no succes. Anyone got an idea? Thanks Bill

Posted by wbzial 4 years ago


PSU bench power supply

My PSU appears to have blown up over the christmas holidays- it was a bit unreliable before, but now it won't boot up my computer at all. I replaced it with a spare from work which works fine, so I now have a not-working 400W PSU I'd like to make a bench power supply from, that will hopefully kick-start my desire to get into microcontroller programming. Does anyone know what the chances are that a broken PSU (no sign of magic smoke, it just doesn't power my computer any more) will still be working enough to use as a DC power supply? If it is, the 'Ibles sometimes disagree- what is the accepted way of keeping it turned on (short a pair of wires, attach a resistor across a pair etc)? It's a 20-pin connector with square 4-pin aux and the usual complement of molex.

Posted by PKM 9 years ago


LED Power supply question

I've got an idea to build a LED light strip for some decorative lighting under a couple of shelves, but it's been more than a few years since I've used my GCSE-level electronics knowledge and I could do with a bit of advice regarding PSUs and parallel connections. I'm thinking of using  two banks of 10 of these LED packages powered by a wall-wart type 12v PSU.  If I wired the individual banks in parallel would I be right in thinking that that would be a current draw of 200mA per bank since each LED has a 20mA requirement, and if both banks were connected to the PSU in parallel I'd need a PSU capable of supplying at least 400ma?

Posted by megahurts 7 years ago


How do I test this PSU?

I had got this PSU for free from PC world, the guy who gave this to me does not know if it works or not... This is my first PSU, I never used one before...So I am asking you how to test this PSU. I hear they have safety wires that must be connected to another wire or something - I don't know...I hope you can help me... Thanks!UPDATEYay! My PSU works :-)Thank you all who helped me!And even better, I do not need to use a power resistor to keep the PSU on!

Posted by Plasmana 9 years ago


Help! (5V psu problems)

Help!I'm trying to make a 5V psu for programming my new (but not so shiny v_v) ATtiny2313'sI've got the circuit shown below set up, but I'm getting out around 5.6V, when the spec sheets say that I'm supposed to be getting out 5V (+/- .2V) I'm using the LM 340t5, just 'cause I don't have any other regs (except for the MC78M05CT, which is basically the same thing.Any Ideas?!EDITI know what was wrong - it was my meter, it really was 5V all along ;)

Posted by T3h_Muffinator 10 years ago


Are high power resistors really neccessary on a benchtop PSU conversion?

Was looking through the site and I was just wondering--why all the huge resistors on the bench-top power supply conversions of PC Power supplies? From personal experience this seems like a waste of perfectly good electricity.I know that they require some current to just stay on however in designing a project for my school's Engineering Technology department I found that the heat generated by such a small resistance (Around 10 ohms) was unacceptably high. Originally I was looking at Instructables and this sitethis site for inspiration but all the cooling measures taken to prevent the high power resistor from becoming a hazard seemed rather silly. A few calculations and experiments later with the 250 watt power supply and I determined that 160 ohm1 watt resistors and 1K 1/2 watt resistors were perfectly acceptable for the purpose of keeping the PSU awake and functioning. I connected one of each between each voltage and ground. According to calculations I can get away with dissipating a grand total of two watts or less spread across multiple resistors.The current divider rule dictates that if you add resistances in parallel, the resulting resistance will be smaller meaning more current will flow through the overall circuit. However this increased current will divide itself across the parallel resistances according to the rule Ix= RtIT/(Rx+Rt). The current through and power dissipated by the resistor you've soldered into the PSU will not change enough to be significant no matter how large or small a resistance you attach in parallel with it--with the exception of an effective short and what in God's name are you doing intentionally shorting the terminals of your bench-top PSU? Now several months later, the PSU is still operating happily and powering multiple micro-controller projects on a display board. Therefore I can reliably conclude that the high-power 10 ohm resistors in many computer power supply conversions are probably a gratuitous waste of wattage. You can get away with using a higher resistance and a resistor that dissipates much less current.

Posted by Psickattus 10 years ago


Wall Wart question.....

I have an NCE cx12v500 direct plug in class 2 transformer in the form of a wall wart. I accepts the USA standard of 120 vAC in, at 60 Hz, and outputs 12 vdc @ 0.5 A. I thought this was the recharging unit for my portable drill, and so I plugged it in. After a few hours of charging, the drill moved but was sluggish. I unplugged it, and when I tested the output, it had dropped to around 1 - 1.3 vdc. I can't seem to find a way into the unit either (molded plastic) without sledge hammer or hacksaw usage coming to mind. Did I fry this one I think I did, but I am looking for a possible, no and solution from someone :-) Aaaargh ! I took it apart finally sawed a notch in it and pried it open... and there was #1: NO regulator *sigh*, and #2: NO fuse of ANY kind, and #3: just a tiny board with a 1,000 uF cap on it and 4 diodes (bridge configuration).....one by one I took components off and tested them with my VOMM and sure enough, all the components were good. Then I tested the transformer......and both sides should have tested closed or short, but one side (output) tested OPEN. *sigh* It fried the transformer ! :-(

Posted by Goodhart 9 years ago


Do Laptops have a "Power On" signal?

I was thinking of trying a project in which I do a custom watercooling setup on a gaming laptop of some kind. I would like the loop to power on and off with the laptop itself, but I don't want to use USB power or something like. That made me wonder if laptops have a power on signal, like desktop psu's have. Do they have it or something similar to a power on signal?

Posted by Dashing Rainbow Dash 2 years ago


Grounding yourself w/ a suitable ESD wristband without a PSU

So I do not own a laptop or any personal computer as I have no need for either of them (until I get deeper into electronic tinkering with an Arduino, etc). I do have an ESD wristband that I bought from a local computer store that has an alligator clip on the end. I've done a bit a research, but only getting mixed answers as to how I can ground myself without a PSU. I'd like to guarantee that I don't fry any of the beginner electronic projects that I plan on doing. How exactly am I supposed to ground myself with an ESD-wristband? I do own rubber Nike sandals (open-toe) that I don't mind wearing to help avoid frying any electronics, have a wooden surface on my workbench, but my workstation area is all on carpet. Thanks in advance!

Posted by TXVisual 1 year ago


Monitor powered by ATX

I searched for hours with varying keywords and can't find too much information...  12v to pin 1 and GND to pin 2 but what do I do about the neutral? I read a xbox 360 laptop mod but it involves the 5v too, and connects it to the power brick. I'm trying to do something different. Trying to make a lunchbox out of a macpro 1.1 case. 1 wire to plug into an outlet is better than needing two. Before I get into this project im trying to understand what I need to buy and feel kinda silly asking such a question which should be extremely simple but I want to be safe and dont want to fry anything. For those that are actually interested in what I'm doing, I kept staring at the case thinking "what can I make with this, and the items I have laying around?" I thought I'd 1-up the basic hackintosh build and go against the grain of using the case how it's intended. I flipped it so the side with the I/O ports were sitting flat, measured the inside which gave me 7" of workable space with 0.4" wiggle room which made perfect for an mini ITX to be laying flat down instead of against the wall. I thought I could take my dremel and cut out an area for a LCD monitor. I have enough DVD drives laying around as well that I could make a "push tray to eject keyboard" sort of slide out keyboard upgrading the rails, using an ultra thin keyboard with a track pad and top it off with sound activated lights and my 1.5 TB HD that's almost full of music. I realize I can do this with a laptop and pocket usb speaker/light effects, but it wouldn't be as cool and I wouldn't get to reuse these items I have sitting around.

Posted by bvarious 3 years ago


Help with a voltage regulator for a DIY bench psu

Hello i have an atx that i would convert into a diy bench power supply but i just realize that it was just 12v and my thing work need more voltage range so i decided to use an old, but still working, Hp 30v ps. so i was looking for a way to regulated it easy, i found the lm2596 and i dont know if it would endure or use lineal regulator such the lm317. so, i need help for any inexpensive alternative or any schematics, or whatever let me step up/down the voltage. Thanks.

Posted by mario.negretemunoz 1 year ago


Fly RC quadcopter with SAITEK X56 and Scherrer Tx700 Pro and Rx700 LR +PSU

Hello can Someone help to connect Saitek Joystick X56 + Scherrer Tx700 Pro + Rx700 LR +PSU in order to fly a quadcopter ? And if it is impossible How to connect the TX700 Pro and the Quanum V52 Ground Control System, please? https://hobbyking.com/en_us/winbox-ground-control-system-v52.html https://hobbyking.com/en_us/rx700lr-psu-reseller.html https://hobbyking.com/en_us/tx700-pro-reseller.html Thanks

Posted by paladin66 1 year ago


Limiting Amps on My power supply

I have a PSU that is capable of 45 amps, but I only need 10 amps. How to I limit the amps? I am using the psu to make chlorate.

Posted by tylerb 10 years ago


ATX PSUI shorting out

​Hi everyone, I hope I did this well, first time on this site, this is a question. I want to make my own soldering iron/heating element, I know I can buy them but it is a project of mine and I just want to know how it works and make it. I used to power a copper wire with a 5V ATX PSU at 16Amps, the psu shorted out and stopped. I read somewhere that you can prevent the PSU from shorting out when there is enough resistance on the wire so the current is not too high for the PSU. (Total nitwit on electronics btw) I was wondering if this is true, and how can I build a succesful soldering iron with a PSU, what transistor or what modifications to make. Also, would a longer wire/rod produce more heat than a shorter? red hot would be nice. Thanks in advance!

Posted by JStuyfzand 2 years ago


(home made lightbox) Keeping backlight on - which pins to bridge on monitor psu board

Thought id seek a bit of pro advice from the forums for my first post as im totally drawing blanks on this one!. i am trying to finish my custom lightbox made from an old hanns.g hh281 monitor. at the moment, when powered on, the backlight turns on then off after a few seconds as no pc signal is being received.  i have taken a picture of the connector to the main board as i cannot figure out which 2 pins to bridge to keep the ccfl backlights on :-( i was guessing one of the ground pin and the on/off  would work but didnt want to mess this up on the first go . any input would be a godsend! thanks all!

Posted by Aikon359 4 years ago


Need a variable power supply... recommendations?

I think its time that I invested in a good desktop variable power supply for building circuits and such. I have one currently, but I'm borrowing it from our school because they have a few extra and don't mind it being gone. But as the school year closes, I am going to have to return it. So any recommendations for a variable desktop supply? My budget is around $100 USD. Thanks!!!

Posted by astroboy907 5 years ago


How can I connect several LEDs to 12v outlet in my PC's PSU?

I have some (about 30: red, gren, blue, white, UV etc.) LEDs laying around in my project box from a high-school project. And I want to make good use of em. so I want to make some kind of mod for my PC. I forgot the voltage of each kind. but they are all 5mm. so I am guessing they will be of very similar voltage. the problem is I have no idea about how to connect em to the available 12v outlets of my PSU. also, I am a novice with LEDs. Any help will be appreciated.

Posted by srk 9 years ago


Some new stuff i got

So recently my dad wanted to throw away a old tv we had that had a bad cord (yeah we could of easily replaced the cord but be have enough tv's..) and i remember seeing plasmana's plasma speaker a while back and that it used a flyback transformer, so i ripped the tv apart taking the pcb with everything on it, speaker, and the coil thingy on the tube, since it was the first time i took one apart i had cliped the magnet wire winding so thats almost no good so i just got rid of that, and then i took apart 3 other monitors i have gotten over the years, one had a set of speakers inside it, and that was interesting to use. and a while back my friend gave me a old 5cd/radio stereo, i would of just kept it using it for the 5 disc changer mostly but the door was broken, and didnt move well at all, so i scraped it and used the speakers. Oh and theres a PSU in there i ripped apart a while ago, i have another but its stored away currently. Anywho heres just a view of what i got, any ideas on what i should make out of all this?

Posted by knexsuperbuilderfreak 4 years ago


Low Voltage Higher Current?

I am having a strange problem on a USB peripheral.... it is a digital radiography sensor that overheats. I believe it may be due to the power supply to the motherboard, but I don't know for sure. I am ASKING FOR YOUR HELP in reasoning out what may be the cause. Anyone with computer/electronics experience, PLEASE HELP!!! I was told that my power supply is too low voltage, and that current is going up in the USB peripheral causing it to heat up. I always thought V=IR means that if voltage drops so does current. But in other places I read that if voltage drops, current goes up so that the wattage/power usage stays the same according to P=VI. So which is it? V=IR or P=VI ? If my power supply has too low voltage, will the current in the device increase to compensate? Or will it just have a lower current? Does it depend on the circuit and the exact electronics in the USB peripheral? Here is my SETUP. It is SIMPLE: Antec AR-350 power supply connected to a motherboard Asus P5N7A-VM in an ATX case. All I have otherwise is a SATA hard drive and a SATA DVD-ROM in there. That's it! Problem started to happen about 1.5 years after I got the computer. That is why I am thinking maybe it is the power supply, or maybe it is the motherboard?  The computer works fine in every other way! It uses Windows XP and has a wireless keyboard/mouse which also works fine. BIOS settings screen Hardware Monitor shows voltage for USB 5v reading about 4.9v, within tolerance. However, one of my USB peripherals is a digital xray sensor. It works ok a few times, then it starts to overheat and fail. This only happens on this computer. When I use another computer (like a laptop) with the same USB hardware it functions ok and never overheats. I don't have any problems on the other computer, even thought I am using the same software/drivers. I bought a different ATX case with a new power supply, and just moved the motherboard, HD and DVD over. Now the motherboard BIOS shows under Hardware Monitor that it is getting 5.2 V instead of 5v, so it is higher! Also the 12 V is higher (around 12.2v) and same for the 3.3V. All the voltages are HIGHER! So I have yet to test this new configuration with the USB peripheral sensor.  Could the motherboard be faulty? I did notice the motherboard looks "curved" with the area under the CPU sort of bulging out. However, with this motherboard you will see there is a huge heat-sink/fan that gets clamped over the CPU and that may be bending the board. Keep in mind the board works perfectly otherwise, so I am wondering WHY it would only affect USB for this one peripheral and not for the keyboard and mouse? Maybe the circuitry on the keyboard/mouse is more tolerant to low voltage? Would appreciate your thoughts please.

Posted by edy 6 years ago


I Hacked a PSU

So I replaced the cheap power supply on my Compaq so I could upgrade my video card. Anyways I'm left over with this 200W PSU and I have no use for it. I opened it up and I see components galore and a 80 MM fan. There is also a bridge rectifier and, some really big transformers, and two giant blue capacitors @ 200v, 470uF. Do I have to remove the PCB to discharge the caps before I start salvaging or is there a better spot. The Chinese that made it also made use of a lot of white hot glue. And the soldering on the PCB just looks plain bad. You guys have any thoughts of what I could do with it? Besides the lab powersupply instructable?

Posted by emuman4evr 10 years ago


PC half dead - not good

Machine will not POST - no beep, BIOS smart fan-control not engaging, PS2 keyboard has no power, monitor reads "no signal" Board does have power - things spin (like the CPU fan which shouldn't until it gets hot) Preceding clues(?) - I thought I'd developed tinnitus, but found it was the PSU (I think) making a high-pitched ringing noise, half the day unplugged and that seemed to go away. Display not engaging properly on start-up: If I waited until the machine got to Windows login and then switch the monitor on - no problem. Switching the monitor on before this point - black sort of standby mode. I think I might try the PSU first, then think about the mainboard. So far I've plugeed and re-plugged things, tried with 0,1 & 2 strips of RAM with no difference. Any suggestions welcome I spent a lot of time replacing 1 cap' in the PSU, then I replaced the PSU (logic being that if I've tampered with it an the thing still doesn't work I should replace it regardless) Then I bought a new board. I was a bloody-sod, CD/DVD still doesn't work... L

Posted by lemonie 8 years ago


ATX PSU to Work Bench PS - Adjustable Voltage and Current question

I am working on converting an old 600W ATX PSU to a bench power supply for me to use for some lab work.  Not everything that I will be plugging into it will have built in current limiting capabilities.  The guide/setup i found on here that I will most likely be following are:  https://www.instructables.com/id/DIY-PSU-into-Bench-Power-supply/  &  http://www.wikihow.com/Convert-a-Computer-ATX-Power-Supply-to-a-Lab-Power-Supply The first link is how I would like mine to end up looking. My PSU is rated as: +3.3V @ 32A +5v @ 50A +12v @ 24A -12v @ 1A -5v @ .5A My end goal is to be able to control the voltage and current output from each binding post.  I will be hooking up a multimeter to this as well and am thinking that i could control what it monitors by some dipswitch setup or switching setup(as far as to which binding posts it's monitoring). I do understand that V = IR.  So keeping 5v but only wanting 3A, i would increase the resistance which is why at first i thought i could play a POT in the circuit.  However after seeing how the voltage regulation was hooked up, I am confused how to do so now since it was connected in the fashion i thought i would need to control the current.  (https://www.instructables.com/files/orig/F2D/LMFU/FYYNECNH/F2DLMFUFYYNECNH.jpg) I would probably use a LM338 since it would allow for more current but again, i would love to be able to have the full 50A available all at one shot but i don't think those IC's allow for that. I am extremely new to all of this and am still learning as well, so if i was able to communicate what i am looking to do correctly and you have a way of explaining it to me, a picture would be awesome if you have the time to create one. :D TYIA for any suggestions.

Posted by agentc0re 7 years ago


relay from USB to turn on exrernal HDD

I found this very interesting forum yesterday, while searching for a way to jump a PSU, to work without the motherboard. I found the answer, then I spent the rest of the night, browsing the forum. I have an idea, but my knowledge of electricity, is very limited. I recently bought an old iMac G3, to tinker with. I have a 160 Gb sata HDD, connected with USB, powered with a PSU, from a dead Dell PC. I want to have the external PSU switched on, using the PS_ON# (green wire) to the COM (black wire), with a USB from the iMac, with a 5 volt relay. I'm looking for any advice, before I do this. I have a little understanding on how relays work (from automotive), but advice about resistors, if any are needed, please be very specific. I did a search, and didn't see any instructable that has been written on this. If this works out, I might try.

Posted by stroked 7 years ago


Wet Computer

I have a Dell Dimension 4600C, but it was ruined when my room was flooded (Thanks Joe the Plumber!). I know the power supply is fried (no power comes out, the circuit board looks white and wet), but I'm not sure if the motherboard is bad. Only the bottom 1/2 inch got wet, and it looks fine. Everything else in the computer works, but the computer was plugged in when it died. Is there a way to test the motherboard (without another computer or PSU)? Should I buy a PSU without knowing if the motherboard works? A new motherboard is too expensive, I might as well get a new computer, but the power supply is only $20. Henry

Posted by -henry- 9 years ago


12VDC from computer power supply WHILE COMPUTER IS RUNNING?

Okay, how crazy would this be? I need a 12VDC power supply to do some bench testing. I have a computer by my workbench which has at least one free Molex connector coming out of the PSU. I know I've seen Instructables that show how to make a bench power supply from a disconnected computer PSU, but would it be a really terrible idea to run wires out the back of the computer case to my bench and use them to test circuits? What are the potential pitfalls, and what are some steps I could take to make them less likely? I'm thinking fuses on the incoming power lines are the first step.

Posted by yoyology 6 years ago


Post little Electronics you have removed/desoldered,ripped off of something(caps,chips,regulators,ext)

I found a Ton of Stuff from a PSU,from diodes to Capacitors to Leds. Post what you have found(in a picture:) ) And maybe your Desktop too.

Posted by ReCreate 9 years ago


[arduino] Computer PSU damaged my servos?

Hi guys! I was hoping You could help me with sort of a problem :( So I bought this Modecom 400W power supply and hooked up 2 servos to molex 5v line and ground. For control signal i used standard arduino uno "example" code. Servos were buzzing for a while but they did not react to commands. Did I need a power driver for the servos? I think they should draw as much current as they need from the line, shouldn't they? So beforehand, I connected the motors directly to arduino for power and they worked. Now - nothing ;/ Nothing inside looks damaged (I think) Anybody had similar problems? Arduino UNO R3 Tower Pro MG 996R

Posted by januszknur 2 years ago


Can We Compare IT Sector with Public Sector Undertaking (PSU), Indian Engineering Services (IES)?

Now a days electronics engineering students have a big problem to select a job in private sector just like a IT SECTOR or in a government sector for example IES or PSU. In my point of view all the above job have good future and good respect and there are some limitation for every sector. If someone ask me this question and i don't have a any choice then my answer is ....... I think we can not compare government sector with IT sector at this stage. Because in govt sector for example IES . Indian Engineering services will give you a huge respect in every sector, promotion, good environment, peaceful life, safety of family etc. When we talk about Public Sector Undertaking (PSU) this will also give you more work experience than IES and promotion, good environment, peaceful life, safety of family etc. Now at last in IT sector this will give you a lot of its depend on your strength. In some cases if you have a potential then you can achieve in few years but in case you are a lazy person then IT sector or private sector will give you nothing and give you a lot of pressure. Finally i conclude this remove your confusion please select your future with your interest, every sector have good scope. Please improve my question and answer with your comment ?

Posted by Abhishek Upadhyay 4 years ago


I AM going to get the project done, but maybe not WORKING before the LED contest ends tonight....

Final touches being done on it.....and then the final test.....I expect it to FAIL MISERABLY,  not discouraging because I will just have to up the power source (change PSU's) and add LED's......I want it to work great when I publish, which may mean it won't make it for the contest....oh well :-)

Posted by Goodhart 7 years ago


Indoor LED plant lights

I am new to posting in the forums, and actually am not even sure if this is being posted in the right area. My name is Ryan, and I need some help. I have been growing spices/herbs for my own recipes for a couple years, and have always used artificial lights. I use a whole wack of those spiral florescent lights (The 23watt ones to replace a 100watt light bulb), and it works alright. I now want to create a panel of LED's so that I can increase my lumen count, and therefore increase the rate of growth. I need help with how to use resistors to get the power to what a 50 LED panel would need. LED: wattage: 1 watt Forward Voltage : 2.1V~2.3V Forward Current: 300mA. ATX Power Supply: Wattage: 250 Normal 120 volt Canadian power I want to make a panel that has 50 1watt LED's in it, power it from a modified 250watt ATX power supply, and if possible, power more than one from a single PSU (Power Supply Unit) (Something like a quick connector setup, have all resistors panel side, and have cords running to the PSU where it uses quick connectors) I want to use the PSU because I have three at my disposal. I was thinking that it would only need 50 watts or something, and I could wire it in series, however I don't know what resistors to use, or where to use them, to make the power work for the LED's. I can wire thing together, solder, and have a basic understanding of circuitry (Like power flows this direction, and this will do that...... don't know numbers)

Posted by MaXoR 9 years ago


Need Places With Free Recycled Computer Hardware

I recently got a job with a non-profit organization to build computers to place in the hands of families who have students and cannot afford computers. Our problem is that we have run out of computer parts that actually work. Does anyone know of any places that will ship parts for free (we may be able to pay for shipping) to northwest Ohio? Its mostly IDE and PATA drives and PSU's and DDR ram we need.

Posted by REA 7 years ago


Help with Voltage Regulator

Hi, I have put one of these together for an ATX power supply and have come across something that I might be getting wrong.... In mocking up the LM317 circuit in breadboard (standar one found everywhere on line and on the LM317 pages), I have got the thing metering -11v to +11v??? I am using one of the black ground wires of the PSU on the black side of the volt meter, but cant figure out why I am not just getting positive voltages??? Could the diode be faulty? Or is this in fact correct? Any help appreciated...

Posted by lone_viper 6 years ago


18Volt 25watt AC to DC power supply.

I have a 18 volt 25 watt power supply I would like to sell. It converts AC to DC and comes with the power cord. I was going to use it to make an adjustable power supply but ended up getting something I liked better. I'm asking for 10 bucks shipped anywhere in the USA. Paypal is what I would like to use for payment. Thanks for looking. Edit: On the board for the psu it says 18 volt but with my volt meter and no load it is showing 19.24.

Posted by r1dd1ck913 5 years ago


Custom Power Supply for Lemax Products

Curious if it would be possible to make a custom power supply for the Lemax Halloween town.  We end up with a tangle of wires every year, and I saw recently This on Amazon and thought it might work.  The only problem I run into is that the bigger Lemax products (houses and spot lights) use 4.5v where as the smaller figurines use 3v.  I've seen a lot of computer PSUs used for benchtop power supplies but none have a 3v or a 4.5v output.  I'm fairly competent with electronics, so I understand this might be more difficult than it's worth.  

Posted by cyranohadden 2 years ago


How do I measure pressure inside computer case

. I've setup a home file server and would like to be able to maintain positive pressure in the case to keep dirt out (two dogs in the house). I've cut some filters to fit the fans blowing into the case (front, rear, and side) and installed a "PCI slot" exhaust fan (it and the PSU are the only exhausts). All these are connected to a four-channel controller.. Using the handy-dandy strip-of-paper-in-front-of-a-case-opening method, case pressure is real close to being equal to ambient with all intake fans on high and the exhaust fan on low (700W PSU has two fans that seem to work very well). Even under full-load, BIOS/SpeedFan says the 1.8 GHz Celeron temp stays below 140 degF under full load and idles in the mid-to-high 90s. HDD temps (2x400GB RAID 1 + spare and 40GB boot) stay below 105, except when formatting when they might rise to 110. . I have some clear tubing, so I could rig up a manometer, but don't feel comfortable hooking up a water hose to my computer. Any ideas on a cheap-and-easy way to measure DeltaP (I'm guessing 0-5 inWC would work) without liquids? Could a automotive Manifold Absolute Pressure (MAP) sensor (I think they have a range close to 0-30 inWC) be adapted?. Someone point me in the right direction and I'll post an Instructable when I figure it out.

Posted by NachoMahma 11 years ago


Best resistor to lower my current?

Hi everyone, I recently started to get into electronics and now need some assistance. I have a 12v and I believe 1A of power. The component I'm connecting is 3.7v with a 450ma battery that uses 3W. I using a l78m05cp, I built what should be a 5v .5A psu, but I must have calculated something wrong because fried my component. I believe the current is what I'm not getting right. Using P=IV, I found I should be using .8A, but I really am not sure about it. Please help, I'll go broke if I keep frying things!

Posted by ramirez_armando 4 years ago


Looking for cheap LiPo 3s low voltagle cutoof/balance circuit

Looking to add portability to a boombox project I built. Want to just grab a LiPo r/c pack and use a 3a 12v SMPS to charge it with. Know of a good battery protection circuit? This will be going to a non tech minded friend. So I'd like him to just be able to plug in the PSU when he is home without the worry of overcharging and be able to run it until the low voltage cut off is hit without worrying about killing the batteries. Any suggestions? It would be for this https://www.instructables.com/id/DIY-Boombox-Ghettoblaster/ Thanks

Posted by Cancerkazoo 5 years ago


Raspberry Pi PC temp checker

Hello forum, I'm planning on buying a raspberry Pi this week. I know a couple programming languages, but only the basics. I've had this idea for quite a while: Connect multiple thermal sensors to the Pi, and then connect the Pi to my old Android cellphone (Nexus 2), and mount the phone to my PC case, so I get read outs for the PC components (CPU, VGA, PSU, HDD, and so on). Can someone help me, and explain how I can do this? I see it as a fun hobby to get into programming, and also reuse a cell phone, so I don't throw it away.

Posted by GeorgeK31 2 years ago


Power LED Help

I'm looking to make some home lighting with LEDs, but I'm not sure how to regulate the current properly. I've really only used resistors up until now for led projects. I have a couple ATX pc power supplies, and I've used it to power an ebay led with no problems. I just touched the led directly to the 3.3v line and ground and it lit up fine. What I'm wondering is, is does the psu automatically adjust the current to what you need? Or is there something else I would need to worry about? (I figured it would be okay to power something off the 3.3V line if they were 3.7V leds, say several P4s)

Posted by opliko 9 years ago


home made PC chase

I made a mini pC the dimensions is: 39 cm W/32 cm/17,5 cm High video: http://www.youtube.com/watch?v=DOEhSknZNq0&feature;=youtu.be my system is: ASUS M4A88T-M LE AMD PHENOM II X4  3 . 4 GHZ Black Edition 2 GB DDR 3  1333 Mhz  KINGSTON   x2  modül 1 TB 32MB Cache SAMSUNG  HDD  7200 Rpm XILENCE XP 500 120 mm Fan PSU 500 Watt DVR-S19 LBK Pioneer  double layer label flash SATA DVD + 2 adet XILENCE with LED 8 cm fan

Posted by trouble01 6 years ago


Just to make sure! 30A to charge battery?

Hey! I have an old home alarm system which is broken beyond repair. I just wanted to make sure if it is OK to charge the 12v battery at 2.1 or2.4 Ah with an ATX PSU at 30A? Will the battry just take 2A from it? If not I have the transformer that came with the Alarm, would that be safe to charge with? It's 12v BTW. Thanks. Never can be too careful. Also, I'm using it on a scanner light tube, this will be fine, yes? I have the starter, it is not a problem. It's weird though, when it is lit, you can pull out the ground on the light tube, not the starter and ut still stays lit. Weird. Thanks in advance!

Posted by Josho 11 years ago


Internal USB converter? Please help!

Hi. I just ordered this, http://www.amazon.co.uk/IB-864-Front-Panel-Reader-Multiport/dp/B004FLEFVU/ref=sr_1_13?ie=UTF8&qid;=1366146730&sr;=8-13&keywords;=icy+box , to connect to a psu I have running on it's own, and with the hope of connecting it to the USB port of my laptop and using it as a USB/Card reader extension kind of thing. Now, rather foolishly I didn't think about how I would connect it to my laptop. I know for sure I can connect it to the PSU with the Molex connector, but how could I connect it to my laptop? This is the connection info it has: USB 3.0 - EXTERNAL to the mainboard or USB 3.0 PCI-X extension card via USB 3.0 cable USB 2.0 hub and card reader: INTERNAL to the mainboard via USB 2.0 cable eSATA: INTERNAL to the mainboard via sata cable Audio: Internal to the mainboard via Audio cable Power: Internal to the system power supply via Big-4Pin Molex Sorry if I'm being stupid, but what concerns me is how it says internal and external, I dont really know what it means, like, is an internal USB 2.0 cable different to an external one, and how could i connect it to a standard USB port? Sorry for the long winded probably really confusing post, basically I just want to know how I can connect this to my laptop's USB port to be able to connect USB devices and use USB sticks and read memory cards lol Really sorry for the bad post, but thanks a lottttt to anyone who can help!!

Posted by DomHawthorn 5 years ago


Cree XB-D driver circuit

Hi Everyone,I would use following design with some modifications to be able to drive 3x3 Cree XB-D LEDs Green/Blue:https://www.instructables.com/id/Circuits-for-usin... Step 8 #4I would use 12V ATX computer PSU as voltage source.PWM source: Arduino nanoAttached picture show how I modified the design: 3x3 LED setupMy main concern, is it correct my calculation of LED currents: based on my understanding, 220mohm current sense resistor setup 2,272A current through FET. Based on Kirchhoff's current law, it will be 757mA for 1 LED.Is that correct?Any advise and suggestion would highly welcome.Thanks,Best Regards,Gyorgy

Posted by bernathg 3 months ago