FETs are further divided into depletion-mode and enhancement-mode types, depending on whether the channel is turned on or off with zero gate-to-source voltage. For enhancement mode, the channel is off at zero bias, and a gate potential can "enhance" the conduction. For the depletion mode, the channel is on at zero bias, and a gate potential (of the opposite polarity) can "deplete" the channel, reducing conduction. For either mode, a more positive gate voltage corresponds to a higher current for n-channel devices and a lower current for p-channel devices. Nearly all JFETs are depletion-mode because the diode junctions would forward bias and conduct if they were enhancement-mode devices; most IGFETs are enhancement-mode types. COUNT 5
QSN1 How are FET's separated? ANS1 depletion-mode and enhancement-mode types QSN2 At what point is a channel off in enhancement-mode? ANS2 at zero bias QSN3 At what point is a channel on in depletion-mode? ANS3 at zero bias QSN4 What channel corresponds with high current? ANS4 n-channel devices QSN5 What channel corresponds with low current? ANS5 p-channel devices