What is the "right way" to step down 12V to 3V (low current applications)

Question

I want to power all my bike lights from a single 12V battery. Most of the little blinky lights I have take 2xAA batteries (3V).

What's the right way to step down from 12V to 3V?

I found this:

http://www.futurlec.com/3V3_Regulator.shtml

...but maybe that's overkill. Any suggestions welcome.

Answer 1

Definitely overkill. A simple 3 terminal regulator would work just fine. If you need current limiting, then a series resistor as Billrus mentioned would do what needs to be done. Just because you found this inverter regulator does not mean that it is your best device to use. It will require more current to operate than what your lamps need. Go to an electronics parts store, Radio Shack will do if you live in the USA, and get a LM317. On the back will be a simple schematic for a simple variable regulator. Buy the parts, assemble the device, and set it for the 3 volts that you need. Actually, I would advise 3.5 to 4 volts, unless of course the lamps are in fact LED's, then I would limit the voltage output to 3-3.5 volts.

Answer 2

That regulator/converter looks good.

Are you sure you are not dealing with LEDs with a VF of 3 volts? they require a series resistor which will raise the voltage to 5 or 6 volts.

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Answer 3

I looked at the web page.  What a bargain!  I would grab it!   You couldn't buy the parts for that price!   Plus, it is a switching regulator which is very efficient.

Good job on finding such a good deal!