I've generally got a good idea how mosfets work. But i've got a couple of questions you've answered hundreds of times before and are getting sick of it. What is high side and low side? Unlike transistors that use current, mosfets are driven by voltage, so why do on a few schematics that i come accross, do they have the gate voltage side listed as 5v and the switch side as a higher voltage, such as 12v? What do people use to drive the gate, if the only power supply is say 12v and the gate needs a minimum of 2v to close?