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12 Cards in this Set
- Front
- Back
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what is the basic voltage gain formula for an open-loop system?
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AV = Vout / Vin
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what is the gain formula for the closed-system?
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Af = AV / 1 - AvBeta
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what are the two classes of feedback?
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positive
negative |
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what are the three types of feedback?
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voltage feedback
current feedback combination feedback |
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what is the purpose of feedback?
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improve stability or improve gain
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why is positive feedback generally not used in amplifier circuits?
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positive feedback = increased gain, decreased stability = decrease in fidelity
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explain degenerative feedback
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a portion of the output signal is fed back out of phase to stabilize changes in the transistor
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why is an amplifier's gain reduced when degenerative feedback is used?
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negative feedback decreases
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why is distortion reduced in a degenerative feedback amplifier?
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because it reduces the changes in the transistor operation
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what is the recognition feature of a shunt voltage feedback amplifier?
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a parallel resistor to input
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why is an amplifier's input resistance increased with series voltage feedback?
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voltage feedback reduces amplifier gain by decreasing Q1's conduction therefore reducing IB
↑Ri = VB → / IB ↓ |
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what is current degeneration
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signal is fedback by an unbypassed emitter resistor
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