5 (887B)
1 mosfet's 2 (metal oxide semiconducting feild effect transistor) 3 voltage controled device 4 has a: 5 drain equivilant to the collector on a transistor 6 gate the base 7 source the emmiter 8 9 no current can flow into the gate 10 11 its just a new kind of transistor for the most part 12 differences between transistor: 13 when it is on, it still conducts slightly (about 0.4V) 14 this is because it has a slight resistance, whereas a transistor does not 15 the small resistance it has is given the name Rdson (something about resistance when on (r d s on)) 16 there is a formula for this in the formula sheet 17 18 a mosfet will start to conduct when the input voltage is 3V unless the question says otherwise 19 20 when ploting a graph of a mosfet, with Vin and I at the drain (Id) the gradient of that line is called gm 21 Id = gm * (Vin - 3) 22 gm is called the transconductance 23 24 the gm and rdson are propertys of the mosfet