emdevelopments

Regulators

Your average regulator has a common ground, a voltage input pin and a voltage output pin. You can smooth the output with capacitors if required.

Note that the input voltage should be higher than the voltage you are limiting it down to, otherwise if the voltage falls below the voltage you are regulating to then the device may switch off. Which can be somewhat inconvenient!

Side note: in most cars the 12V supply is usually about 13.5V. I haven't experienced any problems using a 12V regulator in a car, presumably for this reason.