Electronic Devices and Amplifier Circuits
Electronic Devices and Amplifier Circuits - Orchard Publications
Electronic Devices and Amplifier Circuits - Orchard Publications
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Chapter 4 Field Effect Transistors <strong>and</strong> PNPN <strong>Devices</strong>D+D−NDNDGPPGG+PPGSSSSN – Channel JFETP – Channel JFETFigure 4.4. N−Channel <strong>and</strong> P−Channel JFETsLike in bipolar transistors, one important parameter in FETs is its transconductance g mdefined asthe ratio of the change in current i DS to the change of voltage v GS which produced it. In otherwords,g m=∂i DS-----------∂v GSv DS = constant(4.1)Example 4.1Figure 4.5 shows a common−source N−channel JFET amplifier circuit <strong>and</strong> Table 4.1 shows severalvalues of the current corresponding to the voltage .i DSv GSR +D 1 KΩ15 V −D+vGout−+v i in DS−SV DDFigure 4.5. Common−source N−channel JFET amplifier for Example 4.1TABLE 4.1 Current i DS versus voltage v GS for Example 4.1v GS ( V) 0 – 1– 2– 3– 4i DS ( mA) 35 20 8 2 04−4<strong>Electronic</strong> <strong>Devices</strong> <strong>and</strong> <strong>Amplifier</strong> <strong>Circuits</strong> with MATLAB® / Simulink® / Sim<strong>Electronic</strong>s® Examples, Third EditionCopyright © Orchard Publications
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