ME 340 Chapter 12 summary

ME 340 Chapter 12 summary - When analyzing AC input signals...

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Usman Ansari 04/3/2011 ME 340 ME 340 – Chapter 12 Summary MOSFET transistors can be analyzed in much of the same way as BJT transistors. They operate in either the cutoff, saturation, or triode region. An NMOS transistor is made with a gate that is separated from the body by a silicon dioxide insulator. When voltage is applied between the gate and source terminals, an n-channel layer forms between the drain and source terminals for current to flow into the drain, through the channel, and out the source terminal. Negligible current flows into the gate terminal. Characteristic curves for NMOS and PMOS transistors can be obtained by parameters that depend on the fabrication process of the transistor. By varying the width to length ratio, the amplifier circuit can be altered to obtain the best solution.
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Unformatted text preview: When analyzing AC input signals, the amplified output AC signal usually comes out a little distorted, because of non-uniform spacing of the drain characteristics. FETs are usually biased in the saturation region when used as amplifiers. In a small signal midband frequency analysis, a FET can be modeled by an equivalent circuit with a resistance if the device characteristic has a slope (nonlinear) in the saturation region. In this analysis, we can find the voltage and current gains for the circuit, as well as input and output impedances. The common source amplifier is inverting and can have a voltage gain that is larger than unity. The source follower is non-inverting and has voltage gain that is slightly less than unity, along with high current gain and low output impedance....
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This document was uploaded on 02/16/2012.

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