ME 340 Ch 13 summary

ME 340 Ch 13 summary - Clipping can also occur in the...

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Usman Ansari 03/28/2011 ME 340 ME 340 – Chapter 13 Summary Bipolar Junction Transistors can be made either as npn transistors (in which there is a p-type material sandwiched between two n-type materials), or as pnp transistors (which is just the opposite). A BJT transistor can operate in three basic modes: active, saturation, or cutoff. In the active region, the collector has an amplified version of the base current running through it. In saturation, the collector current does not amplify further with increasing base current, and the transistor acts like a short circuit. In cutoff, there is no current running through the transistor and it acts as an open circuit. Load-line analysis techniques with the common-emitter characteristics can be used to determine the operating point of the transistor. In the active region, signals can be amplified as well as distorted, due to the curvature of the input signal or unequal spacing in the output signal.
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Unformatted text preview: Clipping can also occur in the output signal. The pnp BJT operates in the same manner as the npn, except the current directions and voltage polarities are reversed. In large signal analysis, we can solve for the operating point of the BJT by assuming operating in a certain region, solving the circuit, and then checking to see that the results are consistent with the conditions that need to be satisfied. The four resistor bias circuit is used to bias the BJT in the active region, which is necessary in order to amplify signals. An amplifier in midrange frequencies can be analyzed by the small signal equivalent circuit to determine the gains and impedances of the BJT. The common-emitter amplifier is inverting and has large voltage and current gains, while the emitter-follower amplifier is non-inverting and has near unity voltage gain and large current gain....
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This document was uploaded on 02/16/2012.

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