© The McGraw-Hill Companies, Inc McGraw-Hill 1 PRINCIPLES AND APPLICATIONS OF ELECTRICAL ENGINEERING THIRD EDITION G I O R G I O R I Z Z O N I 9 Transistor Fundamentals

© The McGraw-Hill Companies, Inc McGraw-Hill 2 PRINCIPLES AND APPLICATIONS OF ELECTRICAL ENGINEERING THIRD EDITION G I O R G I O R I Z Z O N I Figure 9.1 Controlled-source models of linear amplifier transistor operation

© The McGraw-Hill Companies, Inc McGraw-Hill 3 PRINCIPLES AND APPLICATIONS OF ELECTRICAL ENGINEERING THIRD EDITION G I O R G I O R I Z Z O N I Figure 9.2 Models of ideal transistor switches i in Voltage-controlled switch Current-controlled switch i in v v + _ i 0 v 0v 0 i 0 + _ r i r i r i r i

© The McGraw-Hill Companies, Inc McGraw-Hill 4 PRINCIPLES AND APPLICATIONS OF ELECTRICAL ENGINEERING THIRD EDITION G I O R G I O R I Z Z O N I Figure 9.4 Bipolar junction transistors

© The McGraw-Hill Companies, Inc McGraw-Hill 5 PRINCIPLES AND APPLICATIONS OF ELECTRICAL ENGINEERING THIRD EDITION G I O R G I O R I Z Z O N I Figure 9.10 Determination of the operation region of a BJT

© The McGraw-Hill Companies, Inc McGraw-Hill 6 PRINCIPLES AND APPLICATIONS OF ELECTRICAL ENGINEERING THIRD EDITION G I O R G I O R I Z Z O N I Figure 9.12 A simplified bias circuit for a BJT amplifier

© The McGraw-Hill Companies, Inc McGraw-Hill 7 PRINCIPLES AND APPLICATIONS OF ELECTRICAL ENGINEERING THIRD EDITION G I O R G I O R I Z Z O N I Figure 9.13 Load-line analysis of a simplified BJT amplifier Collector-emitter voltage, V I B = 250A Q I B = 200A I B = 150A I B = 100A I B = 50A 0 5 m 10 m 15 m 20 m 25 m 30 m 35 m 40 m 45 m 50 m Collector current, A

© The McGraw-Hill Companies, Inc McGraw-Hill 8 PRINCIPLES AND APPLICATIONS OF ELECTRICAL ENGINEERING THIRD EDITION G I O R G I O R I Z Z O N I Figure 9.15 Circuit illustrating the amplification effect in a BJT

© The McGraw-Hill Companies, Inc McGraw-Hill 9 PRINCIPLES AND APPLICATIONS OF ELECTRICAL ENGINEERING THIRD EDITION G I O R G I O R I Z Z O N I Figure 9.16 Amplification of sinusoidal oscillations in a BJT

© The McGraw-Hill Companies, Inc McGraw-Hill 10 PRINCIPLES AND APPLICATIONS OF ELECTRICAL ENGINEERING THIRD EDITION G I O R G I O R I Z Z O N I Figure 9.20 Practical BJT self-bias DC circuit R 1 R 2 R C R E V CC I B I C I E V CE – + V BE – +

© The McGraw-Hill Companies, Inc McGraw-Hill 11 PRINCIPLES AND APPLICATIONS OF ELECTRICAL ENGINEERING THIRD EDITION G I O R G I O R I Z Z O N I Figure 9.21 DC self-bias circuit represented in equivalent-circuit form

© The McGraw-Hill Companies, Inc McGraw-Hill 12 PRINCIPLES AND APPLICATIONS OF ELECTRICAL ENGINEERING THIRD EDITION G I O R G I O R I Z Z O N I Figure 9.22 npn BJT large-signal model

© The McGraw-Hill Companies, Inc McGraw-Hill 13 PRINCIPLES AND APPLICATIONS OF ELECTRICAL ENGINEERING THIRD EDITION G I O R G I O R I Z Z O N I Figure 9.30(a) An n-channel MOSFET is normally off in the absence of an external electric field Source Bulk (substrate) Drain Gate n + n + p D i D V DS V DD V G S _ + _ + _ +

© The McGraw-Hill Companies, Inc McGraw-Hill 14 PRINCIPLES AND APPLICATIONS OF ELECTRICAL ENGINEERING THIRD EDITION G I O R G I O R I Z Z O N I Figure 9.30(d) If the drain and gate supply voltages are both varied a family of curves (shown in Figure 9.31(b)) can be generated, illustrating the MOSFET cutoff, ohmic, saturation, and breakdown regions D i D V DS V GS V DD G S _ _ + _ + + V GG + _

© The McGraw-Hill Companies, Inc McGraw-Hill 15 PRINCIPLES AND APPLICATIONS OF ELECTRICAL ENGINEERING THIRD EDITION G I O R G I O R I Z Z O N I Figure 9.32 n-channel enhancement MOSFET circuit and drain characteristic for Example 9.8

© The McGraw-Hill Companies, Inc McGraw-Hill 16 PRINCIPLES AND APPLICATIONS OF ELECTRICAL ENGINEERING THIRD EDITION G I O R G I O R I Z Z O N I Figure 9.40(a) When the gate-source voltage is lower than - Vp, no current flows. This is the cutoff region SourceDrain Gate nChannel p p

© The McGraw-Hill Companies, Inc McGraw-Hill 17 PRINCIPLES AND APPLICATIONS OF ELECTRICAL ENGINEERING THIRD EDITION G I O R G I O R I Z Z O N I Figure 9.40(b) For small values of drain-source voltage, depletion regions form around the gate sections. As the gate voltage is increased, the depletion regions widen, and the channel width (i.e., the resistance) is controlled by the gate-source voltage. This is the ohmic region of the JFET SourceDrain depletion regions Gate nChannel p p

© The McGraw-Hill Companies, Inc McGraw-Hill 18 PRINCIPLES AND APPLICATIONS OF ELECTRICAL ENGINEERING THIRD EDITION G I O R G I O R I Z Z O N I Figure 9.40(c) As the drain-source voltage is increased, the depletion regions further widen near the drain end, eventually pinching off the channel. This corresponds to the saturation region SourceDrain Pinched-off channel Gate nChannel p p

© The McGraw-Hill Companies, Inc McGraw-Hill 19 PRINCIPLES AND APPLICATIONS OF ELECTRICAL ENGINEERING THIRD EDITION G I O R G I O R I Z Z O N I Figure 9.41 JFET characteristic curves Drain-source voltage, V u 2 m 3 m 4 m 0 V –0.5 V –1.0 V –1.5 V –2.0 V –2.5 V V GS =–3 V Drain Current, A