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DC Barrel Power Jacks and Barrel Size Answered

Recently I was browsing instructables and noticed that there aren't any 'ables on how to figure out what size of DC powerjack one has or even for that matter how those barrel power jacks are measured. One of the major things the DIY Laptop Repair guides overlook is how to identify which DC Jack you have so you can replace it. Most laptop DC jacks don't have part numbers unless they are from a main distributor like DELL. I've been reading a lot of conflicting information as to what really matters when your trying to find a replacement connector component. Some mention barrel length as being important whereas others focus on the inner and outer diameter. It sure would be nice if someone could write up an instructable on how to correctly identify these and what is important when looking for replacement parts like these.


RadioShack is actually a halfway decent source for these (see my I'ble on adding a jack to a toy).

If you've got the "barrel type" (a large round plug with a hole in it, and a socket with a pin in the center) they are specified by the OD of the barrel, and the diameter of the pin. I used a "5.5mm/2.1mm" jack for my project. There are also 5.5/2.5 types, so you really do need to measure them.

What I'd do is take either your laptop, or your AC power block and cables, with you to Radio Shack, and visually compare what you have with the components they sell. The staff may or may not be competent to help you :-/

. The first thing you need to figure out is what the things are called. Then you can search the 'Net for info. I'm assuming that some org (IEC, IEEE, ISO) has specs for all the different types.

. BTW, the "solid" jacks/plugs are commonly called tip and ring. I have no idea what the "tube" type are called.
. From my experience, the plug can't be too long, but it can be too short.