[AFMUG] OT: Electronics Question

[Jason McKemie]

I'm rigging up an Arduino controlled blind setup and trying to configure
the power supply.  The installation will have an Arduino (3.3v) and a servo
that will operate at around 6v.  I was going to supply the whole thing with
6v and use a step-down converter on the Arduino.  Someone recommended using
a diode on the + input, and a cap across the inputs to the step down - how
would I go about sizing these appropriately?