Powering servos and arduino (2)


On an excellent (but now closed) old topic (Powering servos and arduino), I learned a safe way of using one unique power supply to both power my servos and my Arduino.
Basically, the idea is to use a regulated power supply, with enough current (power), and a decoupling filter:

However, still a couple of questions remain:
1-Where in Arduino Uno should I connect the 5V? In Vin? Or perhaps in 5V port? Other?...
2-Where in Arduino Uno should I connect Gnd? In a Gnd? Any Gnd? Other?...

Please clarify.
Thank you!

Connect the 5V in to a 5V pin an GND to a GND pin as you suggest

Ok, I'll do that. Thanks.

Anyway, would that be the same if I connected the 5V to Arduino Vin?

No. The voltage supplied to Vin goes through a voltage regulator to convert it to 5V and this will not work if the input is 5V in the first place

Powering an Uno, that draws about 50mA without anything else connected to it, through an RC filter with a 47ohm resistor doesn't seem right.
That could have a volt-drop across the resistor of 0.05A * 47ohm = 2.35volt,
leaving only 2.65volt for the Uno.
Maybe better to replace the resistor with a (1N5819) Schottky diode.
100uF is also a bit small for brown-out spikes (the Uno already has 47uF).
You could increase that to 470 or 1000uF.

I copied the original schematic from an old closed post. Which I assumed to be correct...

As you may already guessed by know, I'm a beginner... could you please post a basic schematic of what you are proposing? That would help me a lot!

Same diagram, but replace the 47ohm resistor with a diode (cathode/ring on Arduino side).

If you use a Schottky diode, then you only loose ~0.4volt instead of the ~2volt with the resistor.
You could also use a normal diode, but then the loss is about 0.7volt (still ok for an Uno).

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