Electronic – 3 wires on a (bipolar) DC plug – what are they for

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If got this cable as a power plug for my DELL XPS 15. I want to hook it up to a different power source.

But what are the 3! wires for on a bipolar plug?

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Best Answer

There is two reasons. Remote voltage sense as tony suggests.

And because some of these chargers are actually both barrel and center pin, making them have 3 conductors. The third conductor is typically a 1 Wire type data connection, and is used to signal what type of charger is being used.

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Dell and Lenovo use these extensively.

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Based on a few searches for replacement XPS 15 jacks, you have the data pin. Based on your 4 conductor wire, it uses both reasons.