I am trying to run a lcd display in the car. the backlight of the screen is obviously being affected by the alternator as as the RPMs change the rolling of the backlight changes. What would be the simplest way to smooth out the power coming in. The screen runs on 12v (safe 10-14v) and at around 600mA. I was thinking that a simple capacitor inline to the power in on the screen, would act as a filter. Its been many years since Electronics class so I'm not 100% on that. If a cap or anything else, what size/value should I use?