How do I turn off a 12V 3A RGB LED strip? I'm trying to understand how to control an RGB LED strip, I set up all the TIP120 (because I could get my hands on an n-channel mosfet), if I power everything in this way I can change colours and everything:


but now I'm facing a dilemma now, whats the correct way to manage to switch my power strip ON/OFF based on an input from a pir sensor? I mean, how can I handle 12V 3A (requested by my led strip), how do I correctly wire my Arduino up in order to make it switch the LED strip ON/OFF?
That's pretty simple: when you turn off all the colours you are actually turning off the entire strip with very minimum leakage current in each of the three FETs.