Electronics > Beginners

DIY power supply

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MarkF:
Maybe tbe resistor you choose for the LED is too small and the LED shorted out? Try disconnecting it.

Pirateguy:
oh i disconnected everything but the mains in, it still does it.

and i can't find a damn thing wrong with the pcb either.
all caps look good, no brown spots anywhere, nothing.

so screwit, i'm stripping this thing for parts and moving on.

exe:
It seems I'm late to the party. I don't know if you still need a schematic, but here are two designs that are not too bad and can serve while you making something better. Although, honestly, designing a PSU is a hard topic, even a linear one. Me too was trapped into "best beginner's project is a DIY psu" (unless it's a pair of lm317 in serial, one for CC, another one for CV).

For DIY power supply one can take a typical "0-30V 0-3A" PSU. I mean this one: . Can be bought from China as a kit. Don't know its performance. It holds well in my lab, but I don't do much with it. Just be sure to read on the forum how to modify it be more robust, etc. It's worth derate it to 15V max and install a very beefy heatsink.

Another one is mine :) https://www.eevblog.com/forum/beginners/please-critique-this-linear-psu/ . Didn't test how well it switches between CC/CV modes, but step response is excellent (thanks to lt3080). It's my main workhorse so far. Not perfect, worth replacing lm334z with something else as it drifts with temperature. Output current is limited to what lt3080 can provide (1.1A).

Wolfgang:
When I look at the picture, and when I see 90W of regulated output and this ridicuously small line transformer, storage capacitor and cooling, i would suggest
that you put all this in a flameproof environment. In case of a prolonged short circuit at full current this will not last long.

Play safe !

exe:
Oh, god, I didn't even watch the video. Yep, don't do that. Or tune resistor values to limit maximum current. I'd say it's better to change the capacitor anyway as it looks too cheap to be good.

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