How to switch a circuit when it drops below a particular voltage.

[greatsenshi]

Hey guys im a complete beginner when it comes to electronics, however im very keen and I have almost finished my very first project. However I have come across a bit of a snag, the project is portable and uses batteries. I am using these Li-Ion Batteries and they dont like being dropped under 10.8v. I was wondering what the best way of being able to switch the circuit when the voltage drops to around this.

Thanks in advance guys, I hope the question wasnt too stupid.

[kizzap]

Comparator with a reference voltage, controlling the voltage source switch. 

http://home.cogeco.ca/~rpaisley4/xLowBattery.html for a basic idea.

-kizzap

[Gall]

A out-of-the-box solution: power supervisor IC. It's voltage reference plus comparator on a single chip.

[greatsenshi]

Wow thanks for the quick reply. I like the idea of using the TI chip, however im not sure how the Vref input is used.