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Questions and Answers
What type of feedback connection involves connecting the feedback signal in series with the input voltage?
What type of feedback connection involves connecting the feedback signal in series with the input voltage?
Which feedback connection type taps off some output current through the feedback network?
Which feedback connection type taps off some output current through the feedback network?
How does voltage-series feedback affect the overall gain of an amplifier?
How does voltage-series feedback affect the overall gain of an amplifier?
In voltage-shunt feedback, how is the feedback signal connected?
In voltage-shunt feedback, how is the feedback signal connected?
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What is the ratio used to determine output impedance with current-series feedback?
What is the ratio used to determine output impedance with current-series feedback?
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Given an amplifier stage with a gain of $A = -100$, what would the gain with feedback $A_f$ be with $eta = -0.1$?
Given an amplifier stage with a gain of $A = -100$, what would the gain with feedback $A_f$ be with $eta = -0.1$?
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What are the key characteristics of current-shunt feedback?
What are the key characteristics of current-shunt feedback?
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What happens to the input impedance when feedback is applied?
What happens to the input impedance when feedback is applied?
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Study Notes
Feedback Connection Types
- There are four basic types of feedback connections: voltage-series, voltage-shunt, current-series, and current-shunt.
- Voltage refers to connecting the output voltage as input to the feedback network.
- Current refers to tapping off some output current through the feedback network.
- Series refers to connecting the feedback signal in series with the input signal voltage.
- Shunt refers to connecting the feedback signal in parallel with an input current source.
Voltage Series feedback
- A part of the output voltage is fed back in series with the input signal, resulting in an overall gain reduction.
Current Series Feedback
- The output impedance with current-series feedback can be determined by applying a signal V to the output with V s shorted out, resulting in a current I, the ratio of V to I being the output impedance.
Effect of Feedback Connection on Input and Output Impedance
- Feedback connections have a significant effect on the input and output impedance of an amplifier.
- The feedback connection can alter the gain, input impedance, and output impedance of the amplifier.
Voltage Gain, Input and Output Impedance with Feedback for Voltage-Series Feedback
- For voltage-series feedback, the gain with feedback (Af) can be calculated using the formula: Af = A / (1 + β * A) where A is the open-loop gain, β is the feedback factor.
- Input impedance with feedback (Zi) is calculated by: Zi = Zi ( 1 + β * A) where Z i = input impedance without feedback
- Output impedance with feedback (Zo) is calculated by: Zo = Zo / (1 + β * A) where Zo = output impedance without feedback
- The Common Mode Rejection Ratio (CMRR) can be calculated by CMRR = Ad / Ac
- Ac is the gain with feedback for common-mode signals.
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Description
Explore the various types of feedback connections in electronic circuits, including voltage series, current series, voltage shunt, and current shunt. Learn how these feedback types influence input and output impedance, as well as overall circuit gain. This quiz is essential for understanding feedback mechanisms in electronics.
