Let's say I have a very noisy voltage source (caused by moving contacts and vibrations) which is connected to a 7805 voltage regulator, which capacitors should I use to bypass/filter the noise ?
I would assume I should use a capacitor as big as possible ? am I wrong ?
You may want to start with some arc suppression at the source of the noise. Then before and after the regulator a few .1 uF caps as well as some 1,000 uF caps. The latter would depend on the current. Then some bypass caps at the power pins of your components.
The ideal situation would be different power supplies.