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Lecture 1:Intro & Circuit VariablesNilsson 1.1-1.6

ENG17 (Sec. 2): Circuits I

Spring 2014

April 1, 2014

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Overview

• Personal Introduction• Course Introduction• Units• Circuit Analysis• Voltage & Current• Basic Circuit Element• Power & Energy

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Dr. Kyle Montgomery

• B.S. 2004 University of Houston• 3 years @ Schlumberger• M.S. 2008 Purdue University• Ph.D. 2012 Purdue University

– Thesis: Novel Approaches for Wide Bandgap Solar Cells

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What I do now…besides teach…

• Advise students• Research

– Novel solar cells w/compound semiconductors

– New materials for lighting, solar cells, and beyond

– High speed, high power transistors– Alternative energy storage solutions

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Philosophy…on teaching…and life

• Teaching is not confined to classroom time• Conceptual understanding is key• Life really sucks sometimes…how can I

help?

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Overview

• Personal Introduction• Course Introduction• Units• Circuit Analysis• Voltage & Current• Basic Circuit Element• Power & Energy

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ENG17: Circuits 1

• Electrical quantities and elements• Resistive Circuits• Transient and steady-state responses of

RLC circuits• Sinusoidal excitation and phasors• Complex frequency and network functions• Power Calculations

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Course Structure

• TAs– Yuhao Liu (sub: Akash Anand)– Lu Cai– Chi Van Pham– Wu Yu– Xin Zhao

• Course Website is:– http://www.kmontgomery.net/eng17

• Smartsite used primarily for grades• Also using Piazza

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Overview

• Personal Introduction• Course Introduction• Units• Circuit Analysis• Voltage & Current• Basic Circuit Element• Power & Energy

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SI Units

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Derived Units

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Prefixes

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Examples

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Overview

• Personal Introduction• Course Introduction• Units• Circuit Analysis• Voltage & Current• Basic Circuit Element• Power & Energy

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Big Picture

• Need justifies design

• Design specs filter to concept, circuit model, prototype

• Circuit analysis necessary for foundation

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Overview

• Personal Introduction• Course Introduction• Units• Circuit Analysis• Voltage & Current• Basic Circuit Element• Power & Energy

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Test Charge in a Field

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Work & Energy

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Electric Potential Energy

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Voltage

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Atom & Conductor in a Field

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Current

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Ohm’s Law

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Water Analogy

• Water pressure = voltage• Water flow = current

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Overview

• Personal Introduction• Course Introduction• Units• Circuit Analysis• Voltage & Current• Basic Circuit Element• Power & Energy

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Ideal Element

• Passive sign convention

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Fundamental Quantities

1.Voltage (v)2.Current (i)3.Charge (q)4.Flux (Φ)

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Overview

• Personal Introduction• Course Introduction• Units• Circuit Analysis• Voltage & Current• Basic Circuit Element• Power & Energy

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Power ≠ Energy

• Power = Time Derivative of Energy• UNITS!

– Power in Watts– Energy in Watt-hrs or Joules

• Positive Power = Power Delivered to Circuit

• Negative Power = Power Extracted from Circuit

𝑝=𝑑𝑤𝑑𝑡

𝑝=𝑖𝑣

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Recap

• Personal Introduction• Course Introduction• Units• Circuit Analysis• Voltage & Current• Basic Circuit Element• Power & Energy