power inverter

i need to know if there is a way to invert a curent so if there is power coming through the triger it wont open and if there is not the triger is open

You need to explain more: what is the trigger? What do you mean by open? is there a switch somewhere?

hi,

ususaly to do that you have to use an op-amp (operational amplifier)
or if there is some mechanical motion in your device, there are special switches that will close the circuit(let the current pass in a certain direction) if pressed or released.

i did something kind of similar (if i understand what you mean), listen:
i made a device that when a light beam is cutten from a photo-cell (light sensor) a LED will glow. i made this using an op-amp that will invert the current pathing through the LED. (switching the inverting and non-inverting positions so i get the results needed).

if you need more help on op-amps, tell me.