Are there simple governing equations for FETs like there are for BJTs, and if so, what are they? For example, in the BJT case we have IC = β×IB IE + IC + IB I'm sure it depends on the type - MOSFET, JFET, etc. - so anything anyone could contribute would be helpful. From what I understand, the source-to-drain current is proportional to the gate voltage, so if it's linear it would be something like IDS = β×VG From what I've seen Googling IV curves, that's fairly close up until saturation. Am I off base here, or am I on the right track?