Tag: IGFET Amplifiers
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6.12 IGBTs
Because of their insulated gates, IGFETs of all types have extremely high current gain: there can be no sustained gate current if there is no continuous gate circuit in which current may continually flow. The only current we see through the gate terminal of an IGFET, then, is whatever transient (brief surge) may be required…
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6.2 Depletion-type IGFETs
Insulated gate field-effect transistors are unipolar devices just like JFETs: that is, the controlled current does not have to cross a PN junction. There is a PN junction inside the transistor, but its only purpose is to provide that nonconducting depletion region which is used to restrict current through the channel. Schematic Symbol and Physical…
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6.1 Introduction to Insulated-gate Field-effect Transistors
As was stated in the last chapter, there is more than one type of field-effect transistor. The junction field-effect transistor, or JFET, uses voltage applied across a reverse-biased PN junction to control the width of that junction’s depletion region, which then controls the conductivity of a semiconductor channel through which the controlled current moves. Another…