voltage regu;ator....again

[donkey]

hey guys and gals. need a simple schematic for a voltage regulator
I plan to use 4 D batteriesand want an output of 5v. if anyone can help that would be great. if you are really nice could you include a way to monitor battery life too?

 

[Harald Kapp]

Simple solution: low dropout voltage regulator, e.g. LM2940 (or any similar). Drawback: need at least 5.5V at the input, so operated from 4 batteries the output will quickly stop regulating.
Better solution: Use a buck-boost converter, e.g. LTC3534 (500mA) or LTC31112 (2.5A).
Drawback: not so simple.

 

[(*steve*)]

Not so simple, but very cheap from eBay

But you don't get to build it yourself