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| DIY power supply |
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| MarkF:
Here's the Electronic Load and values I used. This does need a fan for the heat sink at currents over 500mA. Maybe @Pirateguy would want to put the chicken before the egg. It's just a matter of putting it together as I already tested it. |
| Pirateguy:
--- Quote from: MarkF on August 20, 2018, 03:53:37 am ---This thread has been throwing a lot of things around. Don't get put off yet. * Your ATX fixed output should be in the can with just a few fuses. This is going to be your workhorse 90% of the time. * The Adjustable Supply is a good project to cut your teeth on. Build it up and do some tests. * Then, try building an Electronic Load. About the same difficulty or easier then the Adj Supply. * After, tackle a Function Generator. It would be a mix of analog design controlled by a microcontroller. (The Arduino's you already have for example.) --- End quote --- lol i'm not put off, but i know my limits and the adjustable current is presently one step too far for me. the ATX one is definitely gonna get built, as well as the volt regulated one. but after that i think ill switch it up and work on some other projects before coming back to the psu. however one of the things i wanna do next is build some mini tesla coils, and i want at least 1 that can be modulated n stuff with an audio jack and a built in func gen, so that will help when i get back to the psu. (i guess ill also be learning much about tiny faraday cages... :P) |
| rstofer:
--- Quote from: Pirateguy on August 20, 2018, 03:38:07 am ---man, i thought this was gonna be simple. lol. this and some other stuff i been reading lately suggests that power supplies in general are kind of an advanced project the moment you make any kind of demands of it's performance. i think i'm gonna have to just build the fixed output ATX one, then the variable voltage one, and then reassess if i want to diy anything more complicated after using that for a while. --- End quote --- This happens all the time. It seems obvious that a power supply should be a first project and many folks recommend it to newcomers. Then reality hits the wall. A REAL lab power supply with a wide range of voltage and current capability coupled with adjustable current limit is a really big project. Dave's project is substantial and I think he got to a dead end (I stand to be corrected on that, I just watched a couple of videos). When you look inside a REAL lab supply you get an understanding of just how complex the project can be. The ATX is a common next idea. The problem is, it doesn't have current limit and current limit is a really important feature. It saves so much on smoked parts. So, one approach that I used for decades is to use wall warts or batteries. I could always put in a 7805 or whatever if I wanted a clean source. Dedicated supplies for each project is one way to go. Even a fixed voltage power supply using 7805,7815 and 7915s will do the job. The output current won't be much but we really don't need 30V at 3A these days. OTOH, Dave did a video or two on these Chinese supplies and they look really capable at about $20 per channel. I don't know anything about them and I did notice that nobody linked them earlier. I don't know why. These are neat looking supplies. There are at least 2 videos because there was a design problem with the earliest models, since corrected. Here's the failure video: And the fix: |
| Pirateguy:
yeah i was looking at those and ill prolly go with that if i ever decide i need a better psu. a loose panel like that provides a lot of freedom over the configuration of the externals. |
| Pirateguy:
quick last question: can i put n led on a negative volt rail? also: what about the polyswitch? |
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