DC jack wiring question....

[trumpus]

What o the different (+) terminals on a standard 2.1 mm boss style jack do?  Are they different?

I want to wire up a box with a 9V and a DC jack, and i've seen one diagram which has both the red lead from the battery snap AND the wire to the LED wired to the same lug, and i have also seen it so that the red lead from the battery snap is wired to one (+) lug (the one closer to the (-) lug) and the LED wired to the other (+) lug.

Does it matter?  How do i wire it so that when i have DC jack plugged in, battery is not being drained?

[LyleCaldwell]

On the jack, there is one lug for the center and two lugs for the sleeve.  Rotate the jack so the center lug is on the left, and that leaves you with one at the top center and one to the right.

Connnect the battery positive to the one on the right, and run from the top center to your circuit.  Connect the left jack to ground.

What happens is : when no 2.1mm plug is  inserted, the top and right lugs are connected together, so the battery positive goes out to the effect.  When you insert the 2.1mm plug, the two lugs are no longer connected, so the battery is not used, and the 2.1mm plug sends it's positive supply to the circuit.

Make sense?

[trumpus]

Completely!   Unfortunately, the only part of my shipment from Small Bear this week, that was mistakenly left out, was the DC jacks, so i don't have it in front of me, but it sounds super clear and when i get 'em i'll do just that!

Thanks a bunch!

Brian