Reduce 5 volts to 3 volts, suggestions? - Page 2 - Electronic Circuits Projects Diagrams Free

justDIY · 20th December 2006, 12:47 PM

a white led can be your shunt diode too, and it's around 3 to 3.3 volts ... of course, you'll only get 10-30ma from it, unless it's a power led.

prprog · 20th December 2006, 05:41 PM

Thanks a lot for you all. So...if I put 3 diodes (1N4004) in series on the "5v positive rail" I will get (more or less) 2.9 volts. Do I need to do the same to the "negative" - diodes in reverse to get -2.9? (...sure this question will make everyone understand how beginner I am). Again thanks a lot.

evandude · 20th December 2006, 10:02 PM

no, you just need them on the positive rail. Whether or not it is a good enough solution depends on your application. if your circuit will work off a not-very-consistent supply voltage then it might be fine, if your circuit is going to be sensitive to supply voltage then it is probably a bad idea.

Since you mentioned the 'tuning' of your circuit and its relation to the supply voltage, I would suspect that using diodes might be a poor choice.

bbarney · 21st December 2006, 04:39 PM

heres another solution
http://www.futurlec.com/Mini_Logic.shtml

evandude · 21st December 2006, 06:02 PM

The OP is looking for a way to regulate a 3v power rail, not to convert logic levels... The only part of that board that would be useful for this would be the 3.3v regulator on it, which could just as easily be purchased alone...

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20th December 2006, 12:47 PM	(permalink)
justDIY	a white led can be your shunt diode too, and it's around 3 to 3.3 volts ... of course, you'll only get 10-30ma from it, unless it's a power led. __________________ If you don't have a planet, what good are gold bars? want to contact me directly? gmail gordonthree check out my project website: http://projects.dimension-x.net Favorite numbers: 09 F9 11 02 9D 74 E3 5B D8 41 56 C5 63 56 88 C0

20th December 2006, 05:41 PM	(permalink)
prprog	Thanks a lot for you all. So...if I put 3 diodes (1N4004) in series on the "5v positive rail" I will get (more or less) 2.9 volts. Do I need to do the same to the "negative" - diodes in reverse to get -2.9? (...sure this question will make everyone understand how beginner I am). Again thanks a lot.

20th December 2006, 10:02 PM	(permalink)
evandude	no, you just need them on the positive rail. Whether or not it is a good enough solution depends on your application. if your circuit will work off a not-very-consistent supply voltage then it might be fine, if your circuit is going to be sensitive to supply voltage then it is probably a bad idea. Since you mentioned the 'tuning' of your circuit and its relation to the supply voltage, I would suspect that using diodes might be a poor choice. __________________ EEgeek.net

21st December 2006, 04:39 PM	(permalink)
bbarney	heres another solution http://www.futurlec.com/Mini_Logic.shtml

21st December 2006, 06:02 PM	(permalink)
evandude	The OP is looking for a way to regulate a 3v power rail, not to convert logic levels... The only part of that board that would be useful for this would be the 3.3v regulator on it, which could just as easily be purchased alone... __________________ EEgeek.net