Electronics > Projects, Designs, and Technical Stuff
My first power supply
queennikki1972:
They say you learn a lot from building power supplies. And I am. My first power supply is straight forward linear power supply. Not a ton of power but enough to power small circuits and toys.
120vac - 12vdc 500ma center tap to bridge rectifier to smoothing - to regulator -to small caps .
Powers on and functions great, still waiting on my fan to come in.
OM222O:
I can't be sure but it seems like you have 2 LDOs in parallel ???
One will back feed the other due to voltages not being exactly the same which is bad
also did you consider a basic voltage adjustment pot? most LDOs are adjustable via a voltage divider circuit which you can make from 1 fixed resistor and 1 pot to allow crude adjustability of the voltage.
queennikki1972:
Each are LM7812 and LM7805. Not adjustable. Not intended to have pot on my first one. Fixed voltages
OM222O:
oh! that makes more sense now. just a quick note, for your smoothing stage you have only used a large electrolytic capacitor. LDOs usually specify a 100n ceramic capacitor on their inputs for noise suppression which you can put in parallel with the electrolytic one. Dave also has a great playlist detailing how to make a decent adjustable power supply which you can watch here:
queennikki1972:
I added the smaller disc caps to the outputs but if needed i can add to the input as well.
And I will review your link
Thank you
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