I'm not pro with electronics and electricity and I want to replace my notebook socket so I'm looking for a coaxial jack dc socket but, as I only have two cables (a positive and a negative one) to solder to the socket, I can't see the purpose of a third solder terminal.
Is it for the grounding or something like that ? Can I use such a socket without using the third terminal ? (If that's the case, which one am I supposed not to use ?).
I know that I could directly buy one with two terminals but that's not the question.