lecture 7: op amps intro & midterm i review nilsson & riedel 5.1-5.3 eng17 (sec. 2):...
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Lecture 7:Op Amps Intro &Midterm I ReviewNilsson & Riedel 5.1-5.3
ENG17 (Sec. 2): Circuits I
Spring 2014
April 22, 2014
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Overview
• Usage• Op Amp Overview• Fundamental
Operation• Basic Op Amp Circuit• Midterm Review
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Usage: Strain Gauge
• Measure strain by measuring change in resistance
• Problem: hard to measure tiny resistance change
Δ𝑅=2𝑅Δ𝐿𝐿
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How to Measure
• Measure voltage across Wheatstone bridge
• Voltage still a small quantity• …Use an Op Amp to amplify the voltage!
Op Amp = Operational Amplifier
Indicates potential to perform math operations
Indicates potential to amplify input signals
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Overview
• Usage• Op Amp Overview• Fundamental
Operation• Basic Op Amp Circuit• Midterm Review
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Op Amp Terminals
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Terminal Voltage / Current
Follows the Node-Voltage Setup All currents set up as going into the “black box”
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Overview
• Usage• Op Amp Overview• Fundamental
Operation• Basic Op Amp Circuit• Midterm Review
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Voltage Transfer Characteristic
A = gain (multiplying constant)
Use “negative feedback” to stay in linear region
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Overview
• Usage• Op Amp Overview• Fundamental
Operation• Basic Op Amp Circuit• Midterm Review
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Op Amp Circuit
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Overview
• Usage• Op Amp Overview• Fundamental
Operation• Basic Op Amp Circuit• Midterm Review
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Difficulties
PS. Don’t forget about units!
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Thevenin / Norton Equivalents
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Superposition
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Max Power Transfer
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Questions?
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Extra Office Hours
• Tomorrow, Wednesday, 5-7pm• Kemper 3101
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Recap
• Usage• Op Amp Overview• Fundamental
Operation• Basic Op Amp Circuit• Midterm Review