I have none to less electronics background, with limited knowledge whatsoever. I've used some schematics from the internet https://www.youtube.com/watch?v=ugDPdgGekNo to put in place the below setup :
A PIR sensor (HC-SR501) + n-Mosfet transistor irfz24n + 9v battery to power on a 9v led light bulb.
The problem is that with this setup, the led light bulb doesn't turn off when no motion is detected, it remains opened. I have measured aside the PIR sensor outputs: it's 3.6V when some motion is detected and when no motion is detected it drops to 0v.
Any advice on what is wrong is appreciated.