easiest, cheapest way to drop 5v to ~2.8v

[johnny13oi]

Hey guys, whats the easiest, cheapest way to drop a 5v input to ~2.8v. The actual thing takes 2AAA but I want it to be under 3V to be on the safe side. Thanks guys

Oh and I can build the circuit if the parts are commonly available.

 

[abvidledUK]

Ω

 

[jrmcferren]

Find out how much current it takes and then use the standard LED resistor formula. Inefficient, but it gets the job done on the cheap (cost of the resistor and time).

 

[mzzj]

http://www.national.com/pf/LM/LM317.html

 

[johnny13oi]

Find out how much current it takes and then use the standard LED resistor formula. Inefficient, but it gets the job done on the cheap (cost of the resistor and time).

Hey, I tried that but it doesnt work. I tested the device draws .05 amps and after I do the resistor formula it draws the correct .05 amps however the device doesnt work ... help please?

 

[mzzj]

Hey, I tried that but it doesnt work. I tested the device draws .05 amps and after I do the resistor formula it draws the correct .05 amps however the device doesnt work ... help please?

Because its doomed not to work.

If you have digital circuitry/non-linear load/variable load resistor trick simply wont work.
Look for the link I gave about LM317.

 

[matrixshaman]

Yes - LM317's are cheap too and easy to build a circuit with only a few components to get good voltage control. However with .05 amps in I'm not sure how it works with that low current (been too long since I've played with these so it might). You should be able to get all components for less than around $2 total if you can find them at some place besides RatShack.