Decoupling capacitors on a bare-bones Arduino

Hey guys, I have a question regarding capacitors :

I recently assembled a bare-bones "Arduino" using an ATMega328P-PU IC, and having followed the instructions on two different tutorials ( one by Nick Gammon and the other an Instructable ) I'm trying to reconcile some differences between their builds.

Nick Gammon places two ceramic 0.1uF capacitors on either side of his breadboard, between power and ground, which I understand eliminates noise and current dips.

The Instructables tutorial however lacks these ceramic capacitors, but includes a 5v voltage regulator LM7805 and two 10uF electrolytic capacitors.

My build has BOTH the voltage regulator and the ceramic capacitors ( and works fine ), but I'm wondering if the ceramic capacitors are unneeded since I'm choosing to have the voltage regulator?

Any feedback is greatly appreciated, thanks!

Let me point out to you that Nick Gammon is way ahead of "instructables" and all of us here would be picking him every time.

The two matters are entirely unrelated. You need the bypass capacitors, that's the end of it. A 7805 is merely one way of providing a regulated 5V supply.

So I understand that I should leave my circuit as-is and there is no redundancy?

Mithra: The Instructables tutorial however lacks these ceramic capacitors...(snip)

Any feedback is greatly appreciated, thanks!

My advice: Remove instructables from your bookmarks. The amount of garbage on there is unbelievable, especially for electronics.

Mithra: So I understand that I should leave my circuit as-is and there is no redundancy?

Very slight redundancy.

A capacitor (10µF or greater) on the input of the regulator to stabilise it.

A capacitor on the output of the regulator to stabilise it. 10µF is unnecessarily large but probably not harmful, 1µF would be quite sufficient.

Ceramic capacitors to bypass high-frequency transients (notably those generated by the MCU itself) on each of the supply terminals at the chip.

fungus: My advice: Remove instructables from your bookmarks. The amount of garbage on there is unbelievable, especially for electronics.

XD XD XD XD XD

Voltage regulators do need bypass capacitors at input and output. Microcontrollers and most IC need bypass capacitors as close as possible to their supply pin.

Thanks guys. I just needed to understand their function!