VGS VDSmax.ġ1 MOSFETs MOSFET Field effect transistor is a unipolar transistor, which acts as a voltage-controlled current device and is a device in which current at two electrodes drain and source is controlled by the action of an electric field at another electrode gate having in-between semiconductor and metal very a thin metal oxide layerġ2 MOSFETs MOSFETs have characteristics similar to JFETs and additionalĬharacteristics that make then very useful. There are three basic operating conditions for a JFET: VGS = 0, VDS increasing to some positive value B. JFET has two p-n junctions under no-bias conditions.ĥ Construction and characteristics of JFET

Top of the n-type channel is connected through an ohmic contact to a terminal referred to as the drain (D) The lower end-connected through an ohmic contact to a terminal referred as source (S) P-type materials are connected together and to the gate (G) terminal. Major part of structure is n-type material. N-channel device will appear as the prominent device with paragraph and section devoted to the impact of using a p-channel. JFET –Junction field effects transistor JFET is a unipolar-transistor, which acts as a voltage controlled current device and is a device in which current at two electrodes is controlled by the action of an electric field at a reversed biased p-n junction.Ĥ Construction and characteristics of JFET FET’s are also generally more static sensitive than BJT’s. FET’s are less sensitive to temperature variations and more easily integrated on IC’s. FET’s also have a higher input impedance, but BJT’s have higher gains.

JFET –Junction field effects transistor MOSFET – Metal oxide semiconductor field effect transistor D-MOSFET ~ Depletion MOSFET E-MOSFET ~ Enhancement MOSFET Similarities: -Amplifiers -Switching devices -Impedance matching circuits Differences: -FET’s are voltage controlled devices whereas BJT’s are current controlled devices.

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