My end goal is to switch a 9V-12V LED strip with an STM-microcontroller (3,3V level logic). So, I'm reading about MOSFETS (n-channel enhancement type in particular), but I'm very confused about the output characteristics and load line graphs.
- In what region should MOSFET operate in "on" state? Linear or saturation?
- What is the point of the load line in the output characteristic? We build a load line with 2 points: Vd=0, I=Vsupply/Rload and Vd=Vsupply, Id=0. Then we find an operating point at our Vg (Vg=3,3V in my case). But what is the point of this if maximum current is at Vd=0? And there is no graph part that corresponds to Vd=0. If Vd=0, Id=0.
- How do I find a MOSFET with a low enough threshold voltage to turn fully on at 3,3V? Thank you!