Bypass battery when DC adapter plugged in

Hi everyone, I'm a total noob to hardware...Ive been a software guy for a few years now but am trying to learn my way around creating circuits.

I have a project that is battery operated. I want to add a 30v adapter to the unit. I would like the circuit to detect the adapter being connected and bypass the battery. Also of course I would like the battery to be used automatically when the adapter is not plugged in. Any ideas how I could do this?

Like I said I am a noob and trying to learn so any help as clear as possible would be greatly appreciated. Thanks! Φ

If you want to switch from battery to DC adapter when plugged in, then you can use a plug with a switch such as this. You connect the battery to the switched terminal. When the adapter is plugged in, it disconnects the battery and the power will come from the adapter.

Awesome, thanks...learning a little bit at a time.