I am trying to understand how to use a MOSFET as a switch. I want to use a microcontroller to control a load using an AOI508 MOSFET as in this schematic:
Now, if this were using a mechanical switch instead of a MOSFET, we could determine the current that would flow through the load using
I=12/1k=12mA. However, the datasheet for my MOSFET shows that, depending on VGS and ID, there will be a voltage drop across drain-source:
So, the true current through the load would be given by Iload=(12-VDS)/Rload. But in order to calculate this we need to know what VDS is, which depends on ID, which depends on Vload, which recursively depends on VDS. Obviously I'm missing something in my understanding but I have no clue what.