review of lectures 05-08review of lectures 05-08 07/23/2013 ece225 circuit analysis. contents of...

CIRCUITS by Ulaby & MaharbizAll rights reserved. Do not reproduce or distribute.

© 2013 National Technology and Science Press

REVIEW OF LECTURES 05-08REVIEW OF LECTURES 05 08

07/23/2013 ECE225 CIRCUIT ANALYSIS

Contents of Midterm #2Midterm #2 Schecule: 10:45~13:15 July 25 Thursday

L t 05 08

Midterm #2 Schecule: 10:45 13:15, July 25, Thursday

Sections 3.5-3.6; 4.3-4.7; 5.2-5.3. Lectures 05-08 Sections 3.5 3.6; 4.3 4.7; 5.2 5.3.

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Summary of Chapter 3 (part 3)y p (p )

All rights reserved. Do not reproduce or distribute. © 2013 National Technology and Science Press

Thévenin’s Theorem

Linear two-terminal circuit can be replaced by an

equivalent circuit composed of a voltage

source and a series resistor

voltage across output with no load (open circuit)

inTh RR

Resistance at terminals with all Resistance at terminals with all independent circuit sources set to zero


Norton’s TheoremAll rights reserved. Do not reproduce or distribute. © 2013 National Technology and Science Press

Linear two-terminal circuit can be replaced by an equivalent be replaced by an equivalent circuit composed of a current source and parallel resistor

Current through output with short circuit

Resistance at terminals with all circuit sources set to zero

How Do We Find Thévenin/Norton E i l t Ci it ?Equivalent Circuits ? Method 1: Open circuit/Short circuit Method 1: Open circuit/Short circuit

1. Analyze circuit to find

2. Analyze circuit to find

Note: This method is applicable to Note: This method is applicable to any circuit, whether or not it contains dependent sources.


Example 3-10: Thévenin Equivalent All rights reserved. Do not reproduce or distribute. © 2013 National Technology and Science Press

p q

How Do We Find Thévenin/Norton E i l t Ci it ?Equivalent Circuits?Method 2: Equivalent ResistanceMethod 2: Equivalent Resistance

1. Analyze circuit to find either

or 2 ll d d b2. Deactivate all independent sources by replacing voltage sources with short circuits and current sources with open circuits.3. Simplify circuit to find equivalent resistance

Note: This method does not apply to circuits that contain dependent sources.p


Example 3-11: RTh


p Th

(Ci i h d d )Replace with SC (Circuit has no dependent sources)

Replace with OC

How Do We Find Thévenin/Norton E i l t Ci it ?Equivalent Circuits?

Method 3:


ExampleExample All rights reserved. Do not

reproduce or distribute. © 2013 National Technology

and Science Press p

E l ( t )


To find

Example (cont.)

Power TransferAll rights reserved. Do not reproduce or distribute. © 2013 National Technology and Science Press

In many situations, we want to y ,maximize power transfer to the load

All rights reserved. Do not reproduce or distribute. © 2013 National Technology

and Science Press

All rights reserved. Do not copy or distribute. © 2013

National Technology and Science Press

Summary of Chapter 4y p

All rights reserved. Do not copy or distribute. © 2013 National Technology and Science Press

Circuit Analysis With Ideal Op AmpsAll rights reserved. Do not copy or distribute. © 2013 National Technology and Science Press

y p p

Use nodal analysis as before, but with “golden rules”

N No current into op amp

No voltage drop across op amp input

Do not apply KCL at op amp output

Noninverting Amplifierg p

At node

021

Rv

Rvv non

spn vvv

so vR

RRv2

21

(max) = Vcc


Inverting Amplifierg p

0 pn vv


Example 4-2: Input Current SourceAll rights reserved. Do not copy or distribute. © 2013 National Technology and Science Press

p pRelate output voltage to input current sourcep

Summing Amplifierg p


Example 4-3: p

Solution:

All rights reserved Do All rights reserved. Do not copy or distribute.


Difference AmplifierAll rights reserved. Do not copy or distribute. © 2013 National Technology and Science Press

p

Note negative gain of channel 1

Voltage FollowerAll rights reserved. Do not copy or distribute. © 2013 National Technology and Science Press

g

“Buffers” Sections of CircuitBuffers Sections of Circuit

depends on both input and load iresistors

is immune to input and load resistors

What is the op amp doing?

Summary of Chapter 5 (Parts 1)All rights reserved. Do not copy or distribute. © 2013 National Technology and Science Press

y p ( )

CapacitorsAll rights reserved. Do not copy or distribute. © 2013 National Technology and Science Press

p

Passive element that stores energy in electric fieldPassive element that stores energy in electric field

Parallel plate capacitor

AdAC

0 1 tdtit

0oC t

For DC, capacitor looks like open circuitlike open circuit

Voltage on capacitor must be continuous (no abrupt change)abrupt change)

Capacitor Response: Given v(t), determine i(t), p(t), and w(t)


C = C =

RC Circuits at dcAll rights reserved. Do not copy or distribute. © 2013 National Technology and Science Press

At dc no currents flow through capacitors: open circuits At dc no currents flow through capacitors: open circuits

Capacitors in Seriesp

Use KVL, current same ,through each capacitor


Capacitors in Parallelp

Use KCL, voltage same , gacross each capacitor

NCCCCC 321eq


Voltage Divisiong


InductorsAll rights reserved. Do not copy or distribute. © 2013 National Technology and Science Press

Passive element that stores energy in magnetic fieldgy g

Solenoid Wound Inductor

0o

1 tidttvL

it

t

At dc, inductor looks like a short circuit

Current through inductor Current through inductor must be continuous (no abrupt change)

AN 2

lANL 2

Inductor Response to p


Inductors in Series

Use KVL, current is same ,through all inductors


Inductors in Parallel

V lt i ll Voltage is same across all inductors

Inductors add together in the same way resistors do


RL Circuits at dcAll rights reserved. Do not copy or distribute. © 2013 National Technology and Science Press

At dc no voltage across inductors: short circuit At dc no voltage across inductors: short circuit

review of lectures 05-08review of lectures 05-08 07/23/2013 ece225 circuit analysis. contents of...

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