I have a 12V power supply that has a female coaxial plug like the one on the right in this image:

Male and female coaxial plugs

I rigged something up with tinfoil just to see if it would work, but it's not ideal at all. Basically, I have two stripped wires that need to connect to the inside and outside of the female plug, respectively. Does anyone know of a trick to do this (DIY) without finding a matching male part?

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    \$\begingroup\$ That looks like a standard barrel jack, not a coaxial connector. \$\endgroup\$
    – David
    Commented Jun 11, 2015 at 7:04
  • \$\begingroup\$ @David I used that term because I didn't know the name, but found this which looks just like it. Will this terminology confuse people? \$\endgroup\$ Commented Jun 11, 2015 at 7:08
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    \$\begingroup\$ Just buy or steal a barrel connector and don't mess around. \$\endgroup\$
    – Andy aka
    Commented Jun 11, 2015 at 7:15
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    \$\begingroup\$ On eBay you can get these: ebay.nl/itm/… Search for "5.5 mm jack", the 5.5 mm being the outer diameter. \$\endgroup\$ Commented Jun 11, 2015 at 7:19

2 Answers 2


I have used soldered multithreaded copper wire for central connector (the pin) and stripped, unsoldered wire wound around and secured by electrical tape on the barrel. That is, before I can get a suitable connector. Even better is to strip off the plug and connect the wires. I'd rather do that that start building a connector. I could try a piece of bent metal sheet as the connector for the barrel. Hint: it doesn't need to be all around the barrel, just touch at some point along the barrel.


I do this occasionally when stuck for a quick connection.

I use stranded or solid wire who's jacket diameter just fits within the inside of the coax plug. Standard jacketed 2 conductor stranded #22 wire fits nicely inside a 2.1mm jack - either shielded or unshielded cable. Cut off the shield if there is one.

Identify the conductor that you want to connect to the outside barrel. Strip about 1.5" - 2" of the conductor insulation and wind the bare conductor tightly around the barrel. You want at least 2 or 3 full turns. Then twist the wire really tightly against itself so as to make a good, solid connection.

You do the outside barrel connection first so that you can twist it easily and get it tight.

Now measure the remaining conductor so that it is about 1/4" longer than the depth of the inside connection. Strip about 3/16" of the jacket, fold it flat against the plastic conductor insulation, then shove it inside the barrel plug. This should be a very tight fit. The bare conductor makes a good connection with the inside of the barrel plug and the conductor insulation provides a compliant pressure to keep the conductor tight.

This is a semi-permanent connection that will last for months or years so long as it is not disturbed. Nonetheless, you really do want to replace it with a proper connector as soon as is practical.

The advantage of this technique is that it doesn't damage the plug. The wires are easily removed when needed.

I'll post photos when I figure out how to do that.


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