External Power supply design for driving multiple loads using arduino uno

[puneet336]

Hi,
In my use case, I need to drive 5 servo motors (sg 90) using arduino uno. I have a power adaptor rated at 9v 1A DC which i plan to use for arduino uno. For the servo motor power supply, i have a 12V 5A adaptor which i plan to convert to 5V 2A using buch convertors.

From this forum , it seems for servo motors the stall current is ~750mA but while running, i guess current requirement may be higher, So to have safety margin i decided to provide atleast 1A to each of the servo motor.

I have attached the circuit diagram with this post.
As the sg90 servo motor 1,2 and 3,4 are connected in parallel to the buck convertor (which is a power source), then we have 5 Volt 1Amp across each of the servo motors. For servo motor 5 we have 5v 2Amp at idle condition.

I have also added a 100uF polar capacitor to "stabilize" the voltage across the motors.

In my case, I may be required to run all the servo motors at a time, Is this power supply design safe for my use case? Please let me know in case something is vague / unclear in my post.

(mod edit)

[Ballscrewbob]

2+2+2 = 6A not 5A but I get where you are coming from.

Also made a small amendment to your pic.

Generally is is usual to have some spare amps for start up surges etc.
But that may also depend on the load on each servo (what is connected to it and how hard it has to work to move that load)

[slipstick]

puneet336:
From this forum , it seems for servo motors the stall current is ~750mA but while running, i guess current requirement may be higher, So to have safety margin i decided to provide atleast 1A to each of the servo motor.

A slight misunderstanding there. The current required by a servo depends on the size and type of servo and in some cases will be a lot more than 1A. But stall current is the maximum current you will ever see, the running current is normally much lower. And the SG90 specification is only 650mA stall current and typical running current is <100mA though that depends on the load. But you should be quite safe in this case.

Steve