| Electronics > Beginners |
| Help me design a PSU |
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| FriedMule:
I would look at some of the videos from Mr. EEV and after that, try to search google for what you decide to make, then put it together and see what happens. If you hit a wall then show your design here on this forum and ask what's wrong. |
| xavier60:
This regulator circuit works well for me. It is possible to just make the positive side only. The current limit is about 600ma. It can be set higher. https://www.eevblog.com/forum/beginners/diy-power-supply-129692/msg1784705/#msg1784705 |
| james_s:
There are lots of linear power supply circuits out there. If you want it to go down to zero, you need a negative bias supply, it doesn't have to deliver much current. Usually there's a separate winding on the transformer for this. |
| VEGETA:
To make it go down to 0v you would need a negative rail. To make this very easy for you, get ICL7660 charge pump IC. Feed it with say 5v and it will output -5v with low current of course. This will be the negative rail of your op-amp which sets the output voltage... it could be something like +25v positive rail and -5v negative rail which will ensure 0v output. It is better to put more filtering caps on 7660 output since it generates lots of noise, or better yes as I did in my dummy load design.. which is to give 9v to 7660 so it outputs -9v (or -8v with losses) then put TL431 after it which generates 2.5v in my case (you can make it anything via 2 resistors) with very low noise, now add another 100uF cap after it and you'll be done. I hope this helps you. |
| Efe_114:
i have a suitable 48v transformer for the banggodd kit i may buy that but i want to learn. a negative bias center tapped etc. transformer is gonna be hard to find in my country . Yes i meant lt3080 . i had some problem troubleshooting my lm317 clrcuits i dont know if my lm317s are fake cuz 1 of them blew up and released a lot of magic smoke and caught on fire at 0.5 amps 12v input 10v output 1 watts heat dissipation i wonder if i can make a stable build out of 2n2222 and 2n3055 npn power transistor and a jellybean lm358 I can make a darlington pair out of 2n2222 and 2n3055 and use it series pass(?) with the vcc(im. NOT good at transistor configuration names)and a classic error amplifier configuration out of lm358 and pot as a referance and output feedback on the another input i think this can go high currents because i will buy 2n3055 in to-3 package or i might stay away from complexity and use lm317 and i wonder if Putting a zener diode reverse biased in Adj pin will work? i dont think so but just want to ask you does minus voltage regulators need minus voltage in the input? If not i may feed -1.25 to the lm317 otherwise i cant because of the availablity problems i mentioned before .sorry for the complex reply :-// I just seen some of these questions got answered while i write this thank you ;D |
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