I have been expierimenting with several transistor circuits, and have a question. If you bias the gate with say 5v, Vdd is 12v, source is 12v. On all three types of transistors (bjt,mosfet, and fet) is it reasonable to expect the drain voltage to be Vgate - Vthreshold? I was using a 339 comparator circuit to ground the gate of a PNP 3906, and the drain of the 3906 to bias the gate of a TIP 3055 to switch on a 12v fan. Poor circuit design led me to get 6v at the gate of the 3055, and the fan was only getting 5v. In order to properly drive the 3055, will I need to provide Vdd - Vthrshold at the gate?