Wires overheated while charging iPad with ATX PSU

Started by s7382 in sci.electronics.design7 months ago 22 replies

https://i.stack.imgur.com/YaRcd.png How it's wired. With my wiring, the USB wires are heating up to around 200-300F. Am I using the right...

https://i.stack.imgur.com/YaRcd.png How it's wired. With my wiring, the USB wires are heating up to around 200-300F. Am I using the right voltage? Is the iPad demanding too much power? The PSU worked fine after the incident.


New Improved +/-45V PSU

Started by Harry D in sci.electronics.design9 years ago 37 replies

Here is my 2W +/-45V PSU http://kvisit.com/S_KuKAw See the MSD7342-224ml for coupled inductor. The IRF9640 is overkill but only SC3...

Here is my 2W +/-45V PSU http://kvisit.com/S_KuKAw See the MSD7342-224ml for coupled inductor. The IRF9640 is overkill but only SC3 model available. The control loop should be pretty straight forward. What is the input voltage range desired? I would copy in that neat net + wiring list that you guys use but do not know how. Just learning LTSPICE. Cheers, Harry


Re-calibrating bench PSU

Started by bitrex in sci.electronics.design2 years ago 11 replies

I need another PSU on my bench and I remembered I had this thing in my junk closet, a SMPS-based supply from www.mpje.com. Something was...

I need another PSU on my bench and I remembered I had this thing in my junk closet, a SMPS-based supply from www.mpje.com. Something was wrong with it I couldn't remember but all I recalled was this is what the power PCB looked like, from the "factory" mind you:


How to turn on this Dell server PSU?

Started by s7382 in sci.electronics.design1 year ago 2 replies

https://i.stack.imgur.com/dJmy2.png It has 3 long pads and 11 shorter pads, which to connect to power on? I can't find a pinout.

https://i.stack.imgur.com/dJmy2.png It has 3 long pads and 11 shorter pads, which to connect to power on? I can't find a pinout.


SMPS +/-5V about +50V supply.

Started by Clive Arthur in sci.electronics.design3 years ago 7 replies

I want a switch mode PSU which will give me two ~2A outputs at 5V above and below a nominal +50V (say +40V to +60V) DC supply, ie +55V and +45V...

I want a switch mode PSU which will give me two ~2A outputs at 5V above and below a nominal +50V (say +40V to +60V) DC supply, ie +55V and +45V from +50V. I can probably work out some fairly clunky ways of doing this, but it seems possible that there's some topology particularly suited to this type of thing. Any thoughts? Cheers -- Clive


PSU capacitor choice

Started by Cursitor Doom in sci.electronics.design2 years ago 15 replies

Greetings, gentlemen, I'm attaching a scan of the rectifier board from an HP8547A network analyser. I'm just wondering how the designer(s)...

Greetings, gentlemen, I'm attaching a scan of the rectifier board from an HP8547A network analyser. I'm just wondering how the designer(s) arrived at the choice of value for the caps across the incoming supply from the mains transformer secondary windings (the caps immediately before the bridge rectifiers)? In case you can't make it out, the values are 0.047uF, 0.22uF, 0.47uF and 0.04...


Weird LLC current limiter

Started by Piotr Wyderski in sci.electronics.design3 years ago 3 replies

I have just found this pretty bizarre idea: http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.665.5375&rep=rep1&type=pdf It uses a...

I have just found this pretty bizarre idea: http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.665.5375&rep=rep1&type=pdf It uses a transformer to limit the voltage swing at the resonant capacitor. Great, but why wouldn't they use a bidirectional TVS for the same purpose? That wouldn't result in a paper, eh, would it? Best regards, Piotr


Low Threshold MOSFET

Started by rickman in sci.electronics.design6 years ago 34 replies

I was looking to order some low current MOSFETs and realized all the popular items had thresholds of 3 volts and higher. I would like to use...

I was looking to order some low current MOSFETs and realized all the popular items had thresholds of 3 volts and higher. I would like to use something that turns on pretty well at 3 volts so it won't need a 5 volt PSU. Any suggestions? I'm looking for a TO-92 case preferably but surface mount will be ok too. I could have sworn some years ago I tracked down a number of low threshold...


OT: Computer power supply on its side?

Started by John Doe in sci.electronics.design2 years ago 4 replies

My PSU has an "economy mode" that turns off the fan most of the time the computer is barely being used (you know, like posting to USENET)....

My PSU has an "economy mode" that turns off the fan most of the time the computer is barely being used (you know, like posting to USENET). However, naturally the design assumes it will be right side up. Does having it on its side and allowing the fan to stop present any overheating hazard to components? Of course normally heat rises. I just cleaned it out. You know how dirty stuff get...


Mains power puzzle

Started by Phil Allison in sci.electronics.design3 years ago 118 replies

Hi to all my pals, on the bench I have a US made, bass instrument amplifier (Eden) in near new condition. It uses a 600VA toroidal tranny...

Hi to all my pals, on the bench I have a US made, bass instrument amplifier (Eden) in near new condition. It uses a 600VA toroidal tranny in the PSU. The "T5A" 20mm AC fuse installed was blown and also a similar previous fuse, I'm told. Nothing wrong found with the amp when a new fuse was fitted. However, repeated switch on testing shows max, peak inrush surges over 120 amps, either ...