Is it safe?

Hi! I have a simple question, will i damage arduino or servo if compounds such as in Figure?

Ty, and sorry on my bad english!

How are you powering the Arduino?

You need to ensure that the Arduino’s ground and the servo’s ground are connected.

Floating grounds often prompt the release of the Magic Smoke™

Arduino is connected to pc via usb cable, is it safe?

Possibly - possibly not. It depends on shared grounding between the PC and the power supply.

Add a wire from GND on the Arduino to GND on the power supply.

Can you recommend the best way to connect the servo to an external power supply? ty

I have done.

What you have is perfectly fine provided you connect the ground of the Arduino to the ground of the servo's power supply.

Also, schematics are better(someone always says that, so I guess I will). It looks like you have -5V attached to the servo instead of +5V. This is also a good way to "prompt the release of the Magic Smoke™"

The big pointy arrow thing says +5V so I guess he's plugged it in wrong...

majenko: The big pointy arrow thing says +5V so I guess he's plugged it in wrong...

Oh yeah. I could barely see them at the same time with that million pixel wide pic.

Oh yeah. I could barely see them at the same time with that million pixel wide pic. [/quote[
Yeah, I had to stand the other side of the room and look through the wrong end of my scanning electron microscope to see it all.

Is this better?

Looks better to me...