Guest ShortCircuitExpert Posted February 1, 2003 Report Share Posted February 1, 2003 Hi MIDIbox'er,i will build my own MIDIbox Plus 16 with the tutorial from Heiko. I would like have an internal power suppply instead of an external one.As anyone can see on my nickname, I'm too stupid :-[ to design a circuit with transformator, rectifier, voltage regulator and so on.Can anyone post a circuit that I can use with my MIDIbox (or all the others for the MBHP-Core)?Thanks a lot! Quote Link to comment Share on other sites More sharing options...
Ian_Hurlock Posted February 2, 2003 Report Share Posted February 2, 2003 HiAll you need to do is go get a small transformer say 500MA.On one side of the transformer ( primary side ) put your 230 / 110 ac volts.Secondary side is the output ac. This goes to your onboard power supply regulator as found on all the projectsIan Quote Link to comment Share on other sites More sharing options...
Guest ShortCircuitExpert Posted February 2, 2003 Report Share Posted February 2, 2003 Thanks for your (really fast) answer, but I'm a little bit careful.Can I use a transformator with 12V and 666mA? A friend told me, that such a trafo produce an effective current about 20V. I guess this is to much for the MC7805C, right? Or what say's "effective current"? Should I better use a transformator with 6V and 500mA? Quote Link to comment Share on other sites More sharing options...
ilmenator Posted February 3, 2003 Report Share Posted February 3, 2003 Hi,go for a 9V model to be on the safe side. 6V is not enough for the 7805 to produce a stable 5V from it, 12V might get a little hot without the use of a cooling metal thing (don't know the exact word for that, sorry - mostly made out of aluminium to spread / dissipate the heat produced by the 7805).Best, ilmenator Quote Link to comment Share on other sites More sharing options...
Ian_Hurlock Posted February 3, 2003 Report Share Posted February 3, 2003 Mmmm................hers's the oil on trannies ( not the dress up ones )Ok transformers usually are a bit underated. Around the 10% mark.So really you are goin to get about 13.5V ACout of your transformer b4 you do any correction.This goes into your bridge rectifier.Bridge rectifiers have four diodes in them. The average voltage drop accross a diode is 0.6v.4 x 0.6 = 2.4 So now you have lost a couple of volts.You can see where this is going eh ;)BTW The cooling thing made of aluminium is a heatsink ;DI crank 15 volts into my 1805's and I think you'll find they are rated to around 25volts. Check the specs on the web.Could be wrong, I was once, says my wife :o ;D ;)Ian Quote Link to comment Share on other sites More sharing options...
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