Power plugs

Thread Starter


Joined May 15, 2015
So I've worked with wall adapters and I know there are different sizes as well as different polarity configurations such as pole + or vv.

But I also understand that pole + is the most common. So polarity aside, I recently got to the point in a prototype where I have to add a power plug but when I went to buy female plugs ran into the issue that they had 2 types of plugs where the diameter of the black outer circle was the same but the metallic inner pin diameter was smaller.

So far I've only seen the description 5.5 x 2.1mm. Which one refers to that metallic inner pin?

Is the outer diameter 5.5 and the inner one 2.1?