Ok and so you can see here we've got the circuit for our lights and it's a pretty basic circuit. We've got our two AA batteries together they produce 3 volts. The power is running through our switch. Turn the switch on and the lights come on. Notice there's two resistors here - those prevent the LEDs from drawing too much current and burning out. The switch opens and closes and lets the power go through. We'll take a closer look at what is inside the switch.