DC jack that disconnects internal batteries when plugged in

[Cozzmo]

Is there a special name for this part?

Have been asked to add an external DC power supply jack to a normally battery powered item, but still retain the battery powered possibility. To avoid issues, i'd like to use a jack that disconnects the internal batteries when the plug is inserted instead of having a switch or something. I know they exist but searching hasn't got me too far (so many items to filter through) finding anything that specifically states that it works in that way. Hoping that somewhere like Jaycar stocks them so i can just pick one up easily.

[RobertHolcombe]

I don't know that there is a name, its just a DC jack socket w/ 3 pins, see below example I found on google

[jeremy]

This can be problematic though, as you will lose power in the changeover. Better have some big capacitors on the power supply!

[wyphy]

Don't know if it helps, but I've always heard this type of jack called a "normaled" jack, just like a relay's normally open/closed connections.

[Refrigerator]

Type in "power jack" in google images and look from there.

[tszaboo]

What is wrong with powerpath controllers?

[German_EE]

As an alternative use a normal jack with diodes in series with the two voltage sources then there will be switching without loss of power.

[Richard Crowley]

IME, it is hard to find a power connector that does NOT have this feature.  That is probably where there is no explicit mention in the descriptions.

[dentaku]

Looking around this room I see that every jack that's visible to me (I use them on breadboards instead of batteries) is the three pin variety that switches when you plug something into them.

[AmmoJammo]

http://www.jaycar.com.au/productView.asp?ID=PS0522

[edavid]

Here are some more of them:  http://www.taydaelectronics.com/hardware/dc-power.html?dir=asc&order=price