Pins on a DC power jack

How do i connect the pins on a DC power jack? Im upgrading from using a battery, and the power jack i have has 3 pins on it. The power supply im plugging into it has a positive center and negative outside. On the jack, the inside appears to have a pin, but the outside appears to be connected to 2 pins. Do i just leave one of these pins floating, or connect both to a single gnd line. Thanks.

did you use your ohmmeter to find where the pins connect..?

The 3-pin jack switches off the battery when you plugin the adapter so the battery doesn't get overcharged and blows-up!
One of the two pins goes to the battery and the other pin goes to the circuit. If you get them backwards, the adapter gets connected to the battery instead of to the circuit.

audioguru said:

The 3-pin jack switches off the battery when you plugin the adapter so the battery doesn't get overcharged and blows-up!
One of the two pins goes to the battery and the other pin goes to the circuit. If you get them backwards, the adapter gets connected to the battery instead of to the circuit.

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that kind of jack..lol,,
i just couldent picture what he was talking about..

Thanks, problem solved.