https://en.wikipedia.org/wiki/MOSFET Likewise, the "oxide" in the name can be a misnomer, as different dielectric materials are used with the aim of obtaining strong channels with smaller applied voltages. http://www.electronics-tutorials.ws/transistor/tran_7.html In the saturation or linear region, the transistor will be biased so that the maximum amount of gate voltage is applied to the device which results in the channel resistance RDS(on being as small as possible with maximum drain current flowing through the MOSFET switch. Therefore the enhancement type MOSFET is switched “Fully-ON”. Spiel: Voltage is kind of like height. I don't have a good analogy of what it would mean to apply height to a terminal. And height requires two points to have height in between. So when we apply a voltage to a switch in a circuit, what are the two points exactly? Voltage at the terminal location to ground?