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ECEN 301 Discussion #20 – Exam 2 Review 1 Date Day Clas s No. Title Chapters HW Due date Lab Due date Exam 10 Nov Mon 20 Exam Review LAB 7 EXAM 2 11 Nov Tue 12 Nov Wed 21 Boolean Algebra 13.2 – 13.3 13 Nov Thu 14 Nov Fri Recitation 15 Nov Sat 16 Nov Sun 17 Nov Mon 22 Combinational Logic 13.3 – 13.5 LAB 10 18 Tue Schedule…

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Page 1: ECEN 301Discussion #20 – Exam 2 Review1 DateDayClass No. TitleChaptersHW Due date Lab Due date Exam 10 NovMon20Exam Review LAB 7 EXAM 2 11 NovTue 12 NovWed21Boolean

ECEN 301 Discussion #20 – Exam 2 Review 1

Date Day ClassNo.

Title Chapters HWDue date

LabDue date

Exam

10 Nov Mon 20 Exam Review

LAB 7

  EXAM 2

11 Nov Tue      

12 Nov Wed 21 Boolean Algebra 13.2 – 13.3  

13 Nov Thu          

14 Nov Fri Recitation  

15 Nov Sat      

16 Nov Sun            

17 Nov Mon 22 Combinational Logic 13.3 – 13.5

LAB 1018 Nov Tue  

Schedule…

Page 2: ECEN 301Discussion #20 – Exam 2 Review1 DateDayClass No. TitleChaptersHW Due date Lab Due date Exam 10 NovMon20Exam Review LAB 7 EXAM 2 11 NovTue 12 NovWed21Boolean

ECEN 301 Discussion #20 – Exam 2 Review 2

Ask

Alma 5:26  26 And now behold, I say unto you, my

brethren, if ye have experienced a change of heart, and if ye have felt to sing the song of redeeming love, I would ask, can ye feel so now?

Page 3: ECEN 301Discussion #20 – Exam 2 Review1 DateDayClass No. TitleChaptersHW Due date Lab Due date Exam 10 NovMon20Exam Review LAB 7 EXAM 2 11 NovTue 12 NovWed21Boolean

ECEN 301 Discussion #20 – Exam 2 Review 3

Lecture 20 – Exam 2 Review

Chapters 4 – 6, 8

Page 4: ECEN 301Discussion #20 – Exam 2 Review1 DateDayClass No. TitleChaptersHW Due date Lab Due date Exam 10 NovMon20Exam Review LAB 7 EXAM 2 11 NovTue 12 NovWed21Boolean

ECEN 301 Discussion #20 – Exam 2 Review 4

Exam 2 12 – 16 November (Monday – Friday) Chapters 4 – 6 and 8 15 questions

12 multiple choice (answer on bubble sheet!)• 1 point each

3 long answer (show your work!)• 4 or 5 points each

Closed book! One 3x5 card allowed

Calculators allowed No time limit Study lecture slides and homework

Page 5: ECEN 301Discussion #20 – Exam 2 Review1 DateDayClass No. TitleChaptersHW Due date Lab Due date Exam 10 NovMon20Exam Review LAB 7 EXAM 2 11 NovTue 12 NovWed21Boolean

ECEN 301 Discussion #20 – Exam 2 Review 5

Exam 2 Review…Overview

1. Capacitors and Inductors2. Measuring Signal Strength3. Phasors4. Impedance5. AC RLC Circuits6. AC Equivalent Circuits7. DC Transient Response8. Frequency Response9. Basic Filters10. Op-Amps

Page 6: ECEN 301Discussion #20 – Exam 2 Review1 DateDayClass No. TitleChaptersHW Due date Lab Due date Exam 10 NovMon20Exam Review LAB 7 EXAM 2 11 NovTue 12 NovWed21Boolean

ECEN 301 Discussion #20 – Exam 2 Review 6

Capacitors & Inductors

Inductors Capacitors

Passive sign convention

Voltage

Current

Power

)()(1

)( 00

tidvL

tit

t L

dt

tdiLtv

)()(

+ L –

i

+ C –

i

)()(1

)( 00

tvdiC

tvt

t C

dt

tdvCti

)()(

dt

tditLitPL

)()()(

dt

tdvtCvtPC

)()()(

Page 7: ECEN 301Discussion #20 – Exam 2 Review1 DateDayClass No. TitleChaptersHW Due date Lab Due date Exam 10 NovMon20Exam Review LAB 7 EXAM 2 11 NovTue 12 NovWed21Boolean

ECEN 301 Discussion #20 – Exam 2 Review 7

Capacitors & Inductors

Inductors Capacitors

Energy

An instantaneous change is not permitted in:

Current Voltage

Will permit an instantaneous change in:

Voltage Current

With DC source element acts as a:

Short Circuit Open Circuit

2)(2

1)( tLitWL 2)(

2

1)( tCvtWC

Page 8: ECEN 301Discussion #20 – Exam 2 Review1 DateDayClass No. TitleChaptersHW Due date Lab Due date Exam 10 NovMon20Exam Review LAB 7 EXAM 2 11 NovTue 12 NovWed21Boolean

ECEN 301 Discussion #20 – Exam 2 Review 8

Capacitors & Inductors

1. What is the difference between the voltage and current behaviour of capacitors and inductors?

Page 9: ECEN 301Discussion #20 – Exam 2 Review1 DateDayClass No. TitleChaptersHW Due date Lab Due date Exam 10 NovMon20Exam Review LAB 7 EXAM 2 11 NovTue 12 NovWed21Boolean

ECEN 301 Discussion #20 – Exam 2 Review 9

Capacitors & Inductors

0.0

1.0

2.0

3.0

4.0

5.0

0.00 2.00 4.00 6.00

0.0

0.1

0.2

0.3

0.4

0.5

0.00 2.00 4.00 6.00

Capacitor voltage vC(t)Inductor current iL(t)

NB: neither can change instantaneously

Capacitor current iC(t)Inductor voltage vL(t)

NB: both can change instantaneously

1. What is the difference between the voltage and current behaviour of capacitors and inductors?

Page 10: ECEN 301Discussion #20 – Exam 2 Review1 DateDayClass No. TitleChaptersHW Due date Lab Due date Exam 10 NovMon20Exam Review LAB 7 EXAM 2 11 NovTue 12 NovWed21Boolean

ECEN 301 Discussion #20 – Exam 2 Review 10

Capacitors & Inductors

2. find the voltage v(t) for a capacitor C = 0.5F with the current as shown and v(0) = 0

0.0

0.2

0.4

0.6

0.8

1.0

1.2

0.0 1.0 2.0 3.0

time (s)

curr

ent

(A)

Page 11: ECEN 301Discussion #20 – Exam 2 Review1 DateDayClass No. TitleChaptersHW Due date Lab Due date Exam 10 NovMon20Exam Review LAB 7 EXAM 2 11 NovTue 12 NovWed21Boolean

ECEN 301 Discussion #20 – Exam 2 Review 11

Capacitors & Inductors

0.0

0.2

0.4

0.6

0.8

1.0

1.2

0.0 1.0 2.0 3.0

time (s)

curr

ent

(A)

t

t

tt

ti

20

211

10

00

:intervals 4in i(t)current

)0(1

)(0

vidC

tvt

2. find the voltage v(t) for a capacitor C = 0.5F with the current as shown and v(0) = 0

Page 12: ECEN 301Discussion #20 – Exam 2 Review1 DateDayClass No. TitleChaptersHW Due date Lab Due date Exam 10 NovMon20Exam Review LAB 7 EXAM 2 11 NovTue 12 NovWed21Boolean

ECEN 301 Discussion #20 – Exam 2 Review 12

Capacitors & Inductors

0.0

0.2

0.4

0.6

0.8

1.0

1.2

0.0 1.0 2.0 3.0

time (s)

curr

ent

(A)

tv

tvd

td

tv

t

t

2)2(0

21)1()1(2

1002

00

:intervals 4in v(t)voltage

1

0

)0(1

)(0

vidC

tvt

2. find the voltage v(t) for a capacitor C = 0.5F with the current as shown and v(0) = 0

Page 13: ECEN 301Discussion #20 – Exam 2 Review1 DateDayClass No. TitleChaptersHW Due date Lab Due date Exam 10 NovMon20Exam Review LAB 7 EXAM 2 11 NovTue 12 NovWed21Boolean

ECEN 301 Discussion #20 – Exam 2 Review 13

Capacitors & Inductors

0.0

0.2

0.4

0.6

0.8

1.0

1.2

0.0 1.0 2.0 3.0

time (s)

curr

ent

(A)

t

tt

tt

tv

23

2112

10

00

:intervals 4in v(t)voltage

2

2. find the voltage v(t) for a capacitor C = 0.5F with the current as shown and v(0) = 0

Page 14: ECEN 301Discussion #20 – Exam 2 Review1 DateDayClass No. TitleChaptersHW Due date Lab Due date Exam 10 NovMon20Exam Review LAB 7 EXAM 2 11 NovTue 12 NovWed21Boolean

ECEN 301 Discussion #20 – Exam 2 Review 14

Capacitors & Inductors

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

0.0 1.0 2.0 3.0 4.0

time (s)

vo

lta

ge

(V

)

0.0

0.2

0.4

0.6

0.8

1.0

1.2

0.0 1.0 2.0 3.0

time (s)

curr

ent

(A)

t

tt

tt

tv

23

2112

10

00

:intervals 4in v(t)voltage

2

NB: The final value of the capacitor voltage after the current source has stopped charging the capacitor depends on two things:1. The initial capacitor voltage2. The history of the capacitor current

2. find the voltage v(t) for a capacitor C = 0.5F with the current as shown and v(0) = 0

Page 15: ECEN 301Discussion #20 – Exam 2 Review1 DateDayClass No. TitleChaptersHW Due date Lab Due date Exam 10 NovMon20Exam Review LAB 7 EXAM 2 11 NovTue 12 NovWed21Boolean

ECEN 301 Discussion #20 – Exam 2 Review 15

Measuring Signal Strength

3. Compute the rms value of the sinusoidal current i(t) = I cos(ωt)

Page 16: ECEN 301Discussion #20 – Exam 2 Review1 DateDayClass No. TitleChaptersHW Due date Lab Due date Exam 10 NovMon20Exam Review LAB 7 EXAM 2 11 NovTue 12 NovWed21Boolean

ECEN 301 Discussion #20 – Exam 2 Review 16

Measuring Signal Strength

2

02

1

)2cos(222

1

)2cos(2

1

2

1

2

)(cos2

)(1

2

/2

0

22

/2

0

2

/2

0

22

0

2

I

I

dI

I

dI

dI

diT

iT

rms

Integrating a sinusoidal waveform over 2 periods equals zero

2

1)2cos()(cos2

tt

3. Compute the rms value of the sinusoidal current i(t) = I cos(ωt)

Page 17: ECEN 301Discussion #20 – Exam 2 Review1 DateDayClass No. TitleChaptersHW Due date Lab Due date Exam 10 NovMon20Exam Review LAB 7 EXAM 2 11 NovTue 12 NovWed21Boolean

ECEN 301 Discussion #20 – Exam 2 Review 17

Measuring Signal Strength

2

02

1

)2cos(222

1

)2cos(2

1

2

1

2

)2(cos2

)(1

2

/2

0

22

/2

0

2

/2

0

22

0

2

I

I

dI

I

dI

dI

diT

iT

rms

The RMS value of any sinusoid signal is always equal to 0.707 times the peak value (regardless of phase or frequency)

3. Compute the rms value of the sinusoidal current i(t) = I cos(ωt)

Page 18: ECEN 301Discussion #20 – Exam 2 Review1 DateDayClass No. TitleChaptersHW Due date Lab Due date Exam 10 NovMon20Exam Review LAB 7 EXAM 2 11 NovTue 12 NovWed21Boolean

ECEN 301 Discussion #20 – Exam 2 Review 18

Phasors4. compute the phasor voltage for the equivalent voltage vs(t)

v1(t) = 15cos(377t+π/4)

v2(t) = 15cos(377t+π/12)

v1(t)+–~

v2(t)+–~

vs(t)+–~

Page 19: ECEN 301Discussion #20 – Exam 2 Review1 DateDayClass No. TitleChaptersHW Due date Lab Due date Exam 10 NovMon20Exam Review LAB 7 EXAM 2 11 NovTue 12 NovWed21Boolean

ECEN 301 Discussion #20 – Exam 2 Review 19

Phasors

v1(t)+–~

v2(t)+–~

vs(t)+–~

1. Write voltages in phasor notation

V

ejV

V

ejV

j

j

1215

15)(

415

15)(

12/2

4/1

4. compute the phasor voltage for the equivalent voltage vs(t)v1(t) = 15cos(377t+π/4)

v2(t) = 15cos(377t+π/12)

Page 20: ECEN 301Discussion #20 – Exam 2 Review1 DateDayClass No. TitleChaptersHW Due date Lab Due date Exam 10 NovMon20Exam Review LAB 7 EXAM 2 11 NovTue 12 NovWed21Boolean

ECEN 301 Discussion #20 – Exam 2 Review 20

Phasors

Vj

jjV

VjV

88.349.14

12sin15

12cos15)(

:rrectangula Convert to12

15)(

2

2

v1(t)+–~

v2(t)+–~

vs(t)+–~

1. Write voltages in phasor notation2. Convert phasor voltages from polar to

rectangular form (see Appendix A)

Vj

jjV

VjV

61.1061.10

4sin15

4cos15)(

:rrectangula Convert to4

15)(

1

1

4. compute the phasor voltage for the equivalent voltage vs(t)v1(t) = 15cos(377t+π/4)

v2(t) = 15cos(377t+π/12)

Page 21: ECEN 301Discussion #20 – Exam 2 Review1 DateDayClass No. TitleChaptersHW Due date Lab Due date Exam 10 NovMon20Exam Review LAB 7 EXAM 2 11 NovTue 12 NovWed21Boolean

ECEN 301 Discussion #20 – Exam 2 Review 21

Phasors

v1(t)+–~

v2(t)+–~

vs(t)+–~

1. Write voltages in phasor notation2. Convert phasor voltages from polar to

rectangular form (see Appendix A)3. Combine voltages

49.1410.25

)()()( 21

j

jVjVjVS

4. compute the phasor voltage for the equivalent voltage vs(t)v1(t) = 15cos(377t+π/4)

v2(t) = 15cos(377t+π/12)

Page 22: ECEN 301Discussion #20 – Exam 2 Review1 DateDayClass No. TitleChaptersHW Due date Lab Due date Exam 10 NovMon20Exam Review LAB 7 EXAM 2 11 NovTue 12 NovWed21Boolean

ECEN 301 Discussion #20 – Exam 2 Review 22

Phasors

v1(t)+–~

v2(t)+–~

vs(t)+–~

1. Write voltages in phasor notation2. Convert phasor voltages from polar to

rectangular form (see Appendix A)3. Combine voltages4. Convert rectangular back to polar

698.28)(

6

10.25

49.14tan

98.28

(14.49)(25.10) r

:polar toConvert

49.1410.25)(

1

22

jV

jjV

S

S

4. compute the phasor voltage for the equivalent voltage vs(t)v1(t) = 15cos(377t+π/4)

v2(t) = 15cos(377t+π/12)

Page 23: ECEN 301Discussion #20 – Exam 2 Review1 DateDayClass No. TitleChaptersHW Due date Lab Due date Exam 10 NovMon20Exam Review LAB 7 EXAM 2 11 NovTue 12 NovWed21Boolean

ECEN 301 Discussion #20 – Exam 2 Review 23

Phasors

v1(t)+–~

v2(t)+–~

vs(t)+–~

1. Write voltages in phasor notation2. Convert phasor voltages from polar to

rectangular form (see Appendix A)3. Combine voltages4. Convert rectangular back to polar5. Convert from phasor to time domain

6377cos98.28)(

698.28)(

ttv

jV

S

S

Bring ωt back

NB: the answer is NOT simply the addition of the amplitudes of v1(t) and v2(t) (i.e. 15 + 15), and the addition of their phases (i.e. π/4 + π/12)

4. compute the phasor voltage for the equivalent voltage vs(t)v1(t) = 15cos(377t+π/4)

v2(t) = 15cos(377t+π/12)

Page 24: ECEN 301Discussion #20 – Exam 2 Review1 DateDayClass No. TitleChaptersHW Due date Lab Due date Exam 10 NovMon20Exam Review LAB 7 EXAM 2 11 NovTue 12 NovWed21Boolean

ECEN 301 Discussion #20 – Exam 2 Review 24

Phasors

v1(t)+–~

v2(t)+–~

vs(t)+–~

6377cos98.28)(

698.28)(

ttv

jV

S

S

Re

Im

14.49 π/6

25.10

Vs(jω)

4. compute the phasor voltage for the equivalent voltage vs(t)v1(t) = 15cos(377t+π/4)

v2(t) = 15cos(377t+π/12)

Page 25: ECEN 301Discussion #20 – Exam 2 Review1 DateDayClass No. TitleChaptersHW Due date Lab Due date Exam 10 NovMon20Exam Review LAB 7 EXAM 2 11 NovTue 12 NovWed21Boolean

ECEN 301 Discussion #20 – Exam 2 Review 25

ImpedanceImpedance: complex resistance (has no physical significance)

will allow us to use network analysis methods such as node voltage, mesh current, etc.

Capacitors and inductors act as frequency-dependent resistors

vs(t)+–~ R

+vR(t)

i(t)

vs(t)+–~ C

+vC(t)

i(t)

vs(t)+–~ L

+vL(t)

i(t)

Vs(jω) +–~

+VZ(jω)

I(jω)

Z

Page 26: ECEN 301Discussion #20 – Exam 2 Review1 DateDayClass No. TitleChaptersHW Due date Lab Due date Exam 10 NovMon20Exam Review LAB 7 EXAM 2 11 NovTue 12 NovWed21Boolean

ECEN 301 Discussion #20 – Exam 2 Review 26

Impedance

LjjZL )(RjZR )(

+L–

+C–

Re

Im

-π/2

π/2R

-1/ωC

ωL

ZR

ZC

ZL

Phasor domain

+R–

CjjZC 1

)(

Vs(jω) +–~

+VZ(jω)

I(jω)

Z

Impedance of resistors, inductors, and capacitors

Page 27: ECEN 301Discussion #20 – Exam 2 Review1 DateDayClass No. TitleChaptersHW Due date Lab Due date Exam 10 NovMon20Exam Review LAB 7 EXAM 2 11 NovTue 12 NovWed21Boolean

ECEN 301 Discussion #20 – Exam 2 Review 27

Impedance

5. find the equivalent impedance (ZEQ)

ω = 104 rads/s, C = 10uF, R1 = 100Ω, R2 = 50Ω, L = 10mH

ZEQ

R2 C

R1

L

Page 28: ECEN 301Discussion #20 – Exam 2 Review1 DateDayClass No. TitleChaptersHW Due date Lab Due date Exam 10 NovMon20Exam Review LAB 7 EXAM 2 11 NovTue 12 NovWed21Boolean

ECEN 301 Discussion #20 – Exam 2 Review 28

Impedance

ZEQ

R2 C

R1

L

)37.1(81.9

62.992.1

51

50

)50)(1010)(10(1

50

1

)/1(

)/1(

||

64

2

2

2

2

21

j

j

j

CRj

R

CjR

CjR

ZZZ CREQ

5. find the equivalent impedance (ZEQ)

ω = 104 rads/s, C = 10uF, R1 = 100Ω, R2 = 50Ω, L = 10mH

Page 29: ECEN 301Discussion #20 – Exam 2 Review1 DateDayClass No. TitleChaptersHW Due date Lab Due date Exam 10 NovMon20Exam Review LAB 7 EXAM 2 11 NovTue 12 NovWed21Boolean

ECEN 301 Discussion #20 – Exam 2 Review 29

Impedance

723.02.136

38.9092.101

62.992.1)10)(10(100

)37.1(81.924

1

11

j

jj

LjR

ZZZZ EQLREQ

ZEQ

R1

L

ZEQ1

)37.1(81.91EQZNB: at this frequency (ω) the circuit has an inductive impedance (reactance or phase is positive)

5. find the equivalent impedance (ZEQ)

ω = 104 rads/s, C = 10uF, R1 = 100Ω, R2 = 50Ω, L = 10mH

Page 30: ECEN 301Discussion #20 – Exam 2 Review1 DateDayClass No. TitleChaptersHW Due date Lab Due date Exam 10 NovMon20Exam Review LAB 7 EXAM 2 11 NovTue 12 NovWed21Boolean

ECEN 301 Discussion #20 – Exam 2 Review 30

AC RLC CircuitsAC Circuit Analysis

1. Identify the AC sources and note the excitation frequency (ω)

2. Convert all sources to the phasor domain3. Represent each circuit element by its impedance4. Solve the resulting phasor circuit using network

analysis methods5. Convert from the phasor domain back to the time

domain

Page 31: ECEN 301Discussion #20 – Exam 2 Review1 DateDayClass No. TitleChaptersHW Due date Lab Due date Exam 10 NovMon20Exam Review LAB 7 EXAM 2 11 NovTue 12 NovWed21Boolean

ECEN 301 Discussion #20 – Exam 2 Review 31

AC RLC Circuits

6. find ia(t) and ib(t)vs(t) = 15cos(1500t)V, R1 = 100Ω, R2 = 75Ω, L = 0.5H, C = 1uF

R1

vs(t)+–~

R2

L

C

ia(t) ib(t)

Page 32: ECEN 301Discussion #20 – Exam 2 Review1 DateDayClass No. TitleChaptersHW Due date Lab Due date Exam 10 NovMon20Exam Review LAB 7 EXAM 2 11 NovTue 12 NovWed21Boolean

ECEN 301 Discussion #20 – Exam 2 Review 32

AC RLC Circuits

6. find ia(t) and ib(t)vs(t) = 15cos(1500t)V, R1 = 100Ω, R2 = 75Ω, L = 0.5H, C = 1uF

R1

vs(t)+–~

R2

L

C

ia(t) ib(t)

1. Note frequencies of AC sources

Only one AC source - ω = 1500 rad/s

Page 33: ECEN 301Discussion #20 – Exam 2 Review1 DateDayClass No. TitleChaptersHW Due date Lab Due date Exam 10 NovMon20Exam Review LAB 7 EXAM 2 11 NovTue 12 NovWed21Boolean

ECEN 301 Discussion #20 – Exam 2 Review 33

AC RLC Circuits

6. find ia(t) and ib(t)vs(t) = 15cos(1500t)V, R1 = 100Ω, R2 = 75Ω, L = 0.5H, C = 1uF

R1

vs(t)+–~

R2

L

C

ia(t) ib(t)

1. Note frequencies of AC sources2. Convert to phasor domain

ZR1

Vs(jω)+–~

ZR2

Ia(jω)

ZL

ZC

Ib(jω)

Page 34: ECEN 301Discussion #20 – Exam 2 Review1 DateDayClass No. TitleChaptersHW Due date Lab Due date Exam 10 NovMon20Exam Review LAB 7 EXAM 2 11 NovTue 12 NovWed21Boolean

ECEN 301 Discussion #20 – Exam 2 Review 34

AC RLC Circuits

6. find ia(t) and ib(t)vs(t) = 15cos(1500t)V, R1 = 100Ω, R2 = 75Ω, L = 0.5H, C = 1uF

ZR1

Vs(jω)+–~

ZR2

Ia(jω)

ZL

ZC

Ib(jω)

1. Note frequencies of AC sources2. Convert to phasor domain3. Represent each element by its impedance

10011 RZR

015015)(

)cos(15)(j

s

s

ejV

ttv

7522 RZR

750

)5.0)(1500(

j

j

LjZL

667

)10)(1500(/1

/16

j

j

CjZC

Page 35: ECEN 301Discussion #20 – Exam 2 Review1 DateDayClass No. TitleChaptersHW Due date Lab Due date Exam 10 NovMon20Exam Review LAB 7 EXAM 2 11 NovTue 12 NovWed21Boolean

ECEN 301 Discussion #20 – Exam 2 Review 35

AC RLC Circuits

6. find ia(t) and ib(t)vs(t) = 15cos(1500t)V, R1 = 100Ω, R2 = 75Ω, L = 0.5H, C = 1uF

0)(

0)(

0)()()(

:bat KVL

2

2

2

RLCbCa

RbLbCba

RLC

ZZZIZI

ZIZIZII

jVjVjV

+ZR1–

Vs(jω)+–~

+ZR2

–Ia(jω)

+ZL–

+ZC

– Ib(jω)

667

750

75

100

2

1

jZ

jZ

Z

Z

C

L

R

R

4. Solve using network analysis• Mesh current

sCbCRa

sCbaRa

CRs

VZIZZI

VZIIZI

jVjVjV

)(

)(

0)()()(

:aat KVL

1

1

1

Page 36: ECEN 301Discussion #20 – Exam 2 Review1 DateDayClass No. TitleChaptersHW Due date Lab Due date Exam 10 NovMon20Exam Review LAB 7 EXAM 2 11 NovTue 12 NovWed21Boolean

ECEN 301 Discussion #20 – Exam 2 Review 36

AC RLC Circuits

6. find ia(t) and ib(t)vs(t) = 15cos(1500t)V, R1 = 100Ω, R2 = 75Ω, L = 0.5H, C = 1uF

0)8375()667( jIjI ba

+ZR1–

Vs(jω)+–~

+ZR2

–Ia(jω)

+ZL–

+ZC

– Ib(jω)

AI

AI

49.1019.0

917.00032.0

2

1

4. Solve using network analysis• Mesh current

15)667()667100( jIjI ba

Page 37: ECEN 301Discussion #20 – Exam 2 Review1 DateDayClass No. TitleChaptersHW Due date Lab Due date Exam 10 NovMon20Exam Review LAB 7 EXAM 2 11 NovTue 12 NovWed21Boolean

ECEN 301 Discussion #20 – Exam 2 Review 37

AC RLC Circuits

6. find ia(t) and ib(t)vs(t) = 15cos(1500t)V, R1 = 100Ω, R2 = 75Ω, L = 0.5H, C = 1uF

+ZR1–

Vs(jω)+–~

+ZR2

–Ia(jω)

+ZL–

+ZC

– Ib(jω) mAtti

AI

)917.01500cos(2.3)(

917.00032.0

1

1

5. Convert to Time domain

mAtti

AI

)49.11500cos(19)(

49.1019.0

2

2

Page 38: ECEN 301Discussion #20 – Exam 2 Review1 DateDayClass No. TitleChaptersHW Due date Lab Due date Exam 10 NovMon20Exam Review LAB 7 EXAM 2 11 NovTue 12 NovWed21Boolean

ECEN 301 Discussion #20 – Exam 2 Review 38

AC Equivalent CircuitsThévenin and Norton equivalent circuits apply in AC analysis

Equivalent voltage/current will be complex and frequency dependent

Load

+V–

I

Source

VT(jω)+–

ZT

Load

+

V

I

IN(jω)

ZN Load

+

V

I

Norton EquivalentThévenin Equivalent

Page 39: ECEN 301Discussion #20 – Exam 2 Review1 DateDayClass No. TitleChaptersHW Due date Lab Due date Exam 10 NovMon20Exam Review LAB 7 EXAM 2 11 NovTue 12 NovWed21Boolean

ECEN 301 Discussion #20 – Exam 2 Review 39

AC Equivalent CircuitsComputation of Thévenin and Norton Impedances:

1. Remove the load (open circuit at load terminal)2. Zero all independent sources

Voltage sources short circuit (v = 0) Current sources open circuit (i = 0)

3. Compute equivalent impedance across load terminals (with load removed)

NB: same procedure as equivalent resistance

ZL

Z1

Vs(jω)

+–

Z3

Z2

Z4

a

b

Z1 Z3

Z2

Z4

a

b

ZT

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ECEN 301 Discussion #20 – Exam 2 Review 40

AC Equivalent CircuitsComputing Thévenin voltage:

1. Remove the load (open circuit at load terminals)2. Define the open-circuit voltage (Voc) across the load terminals3. Chose a network analysis method to find Voc

node, mesh, superposition, etc.

4. Thévenin voltage VT = Voc

Z1

Vs(jω)

+–

Z3

Z2

Z4

a

b

Z1

Vs(jω)

+–

Z3

Z2

Z4

a

b

+VT

NB: same procedure as equivalent resistance

Page 41: ECEN 301Discussion #20 – Exam 2 Review1 DateDayClass No. TitleChaptersHW Due date Lab Due date Exam 10 NovMon20Exam Review LAB 7 EXAM 2 11 NovTue 12 NovWed21Boolean

ECEN 301 Discussion #20 – Exam 2 Review 41

AC Equivalent CircuitsComputing Norton current:

1. Replace the load with a short circuit2. Define the short-circuit current (Isc) across the load terminals3. Chose a network analysis method to find Isc

node, mesh, superposition, etc.

4. Norton current IN = Isc

Z1

Vs(jω)

+–

Z3

Z2

Z4

a

b

Z1

Vs(jω)

+–

Z3

Z2

Z4

a

b

IN

NB: same procedure as equivalent resistance

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ECEN 301 Discussion #20 – Exam 2 Review 42

AC Equivalent Circuits

7. find the Thévenin equivalentω = 103 Hz, Rs = 50Ω, RL = 50Ω, L = 10mH, C = 0.1uF

Rs

vs(t)+–~ RL

L

C +vL

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ECEN 301 Discussion #20 – Exam 2 Review 43

AC Equivalent Circuits

7. find the Thévenin equivalentω = 103 Hz, Rs = 50Ω, RL = 50Ω, L = 10mH, C = 0.1uF

Rs

vs(t)+–~ RL

L

C +vL

1. Note frequencies of AC sources

Only one AC source - ω = 103 rad/s

Page 44: ECEN 301Discussion #20 – Exam 2 Review1 DateDayClass No. TitleChaptersHW Due date Lab Due date Exam 10 NovMon20Exam Review LAB 7 EXAM 2 11 NovTue 12 NovWed21Boolean

ECEN 301 Discussion #20 – Exam 2 Review 44

AC Equivalent Circuits

7. find the Thévenin equivalentω = 103 Hz, Rs = 50Ω, RL = 50Ω, L = 10mH, C = 0.1uF

Rs

vs(t)+–~ RL

L

C +vL

1. Note frequencies of AC sources2. Convert to phasor domain

Zs

ZLD

+–~

ZL

ZC

Vs(jω)

Page 45: ECEN 301Discussion #20 – Exam 2 Review1 DateDayClass No. TitleChaptersHW Due date Lab Due date Exam 10 NovMon20Exam Review LAB 7 EXAM 2 11 NovTue 12 NovWed21Boolean

ECEN 301 Discussion #20 – Exam 2 Review 45

AC Equivalent Circuits

7. find the Thévenin equivalentω = 103 Hz, Rs = 50Ω, RL = 50Ω, L = 10mH, C = 0.1uF

1. Note frequencies of AC sources2. Convert to phasor domain3. Find ZT

• Remove load & zero sources

Zs

ZL

ZC

9182.033.82

414.65501

)/1()(

)/1)((

||

2

jLC

LjR

CjLj

CjLjR

ZZZZ

S

S

LCST

Page 46: ECEN 301Discussion #20 – Exam 2 Review1 DateDayClass No. TitleChaptersHW Due date Lab Due date Exam 10 NovMon20Exam Review LAB 7 EXAM 2 11 NovTue 12 NovWed21Boolean

ECEN 301 Discussion #20 – Exam 2 Review 46

AC Equivalent Circuits

7. find the Thévenin equivalentω = 103 Hz, Rs = 50Ω, RL = 50Ω, L = 10mH, C = 0.1uF

9182.033.82 TZ

1. Note frequencies of AC sources2. Convert to phasor domain3. Find ZT

• Remove load & zero sources4. Find VT(jω)

• Remove load

Zs

+–~

ZL

ZC

Vs(jω)+

VT(jω)–

NB: Since no current flows in the circuit once the load is removed:

ST VV

Page 47: ECEN 301Discussion #20 – Exam 2 Review1 DateDayClass No. TitleChaptersHW Due date Lab Due date Exam 10 NovMon20Exam Review LAB 7 EXAM 2 11 NovTue 12 NovWed21Boolean

ECEN 301 Discussion #20 – Exam 2 Review 47

AC Equivalent Circuits

7. find the Thévenin equivalentω = 103 Hz, Rs = 50Ω, RL = 50Ω, L = 10mH, C = 0.1uF

9182.033.82 TZST VV

Zs

ZLD

+–~

ZL

ZC

Vs(jω)

ZT

+–~

VT(jω)

ZLD

Page 48: ECEN 301Discussion #20 – Exam 2 Review1 DateDayClass No. TitleChaptersHW Due date Lab Due date Exam 10 NovMon20Exam Review LAB 7 EXAM 2 11 NovTue 12 NovWed21Boolean

ECEN 301 Discussion #20 – Exam 2 Review 48

DC Transient Response

Transient response of a circuit consists of 3 parts:1. Steady-state response prior to the switching on/off of a

DC source2. Transient response – the circuit adjusts to the DC source3. Steady-state response following the transient response

R1

R2 Cvs+–

t = 0

DC Source

Switch Energy element

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ECEN 301 Discussion #20 – Exam 2 Review 49

Initial condition x(0): DC steady state before a switch is first activated x(0–): right before the switch is closed x(0+): right after the switch is closed

Final condition x(∞): DC steady state a long time after a switch is activated

R1

R2

Cvs

+–

t = 0

R3

R1

R2

Cvs

+–

t → ∞

R3

Initial condition Final condition

DC Transient Response – DC Steady-State

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ECEN 301 Discussion #20 – Exam 2 Review 50

Remember – capacitor voltages and inductor currents cannot change instantaneouslyCapacitor voltages and inductor currents don’t change right

before closing and right after closing a switch

)0()0(

)0()0(

LL

CC

ii

vv

DC Transient Response – DC Steady-State

Page 51: ECEN 301Discussion #20 – Exam 2 Review1 DateDayClass No. TitleChaptersHW Due date Lab Due date Exam 10 NovMon20Exam Review LAB 7 EXAM 2 11 NovTue 12 NovWed21Boolean

ECEN 301 Discussion #20 – Exam 2 Review 51

DC Transient Response – DC Steady-State

8. find the initial and final current conditions at the inductoris = 10mA

is

t = 0

RLiL

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ECEN 301 Discussion #20 – Exam 2 Review 52

8. find the initial and final current conditions at the inductoris = 10mA

is

t = 0

RLiL

1. Initial conditions – assume the current across the inductor is in steady-state.

isiL

NB: in DC steady state inductors act like short circuits, thus no current flows through R

DC Transient Response – DC Steady-State

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ECEN 301 Discussion #20 – Exam 2 Review 53

8. find the initial and final current conditions at the inductoris = 10mA 1. Initial conditions – assume the current

across the inductor is in steady-state.

mA

ii sL

10

)0(

is

iL

DC Transient Response – DC Steady-State

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ECEN 301 Discussion #20 – Exam 2 Review 54

8. find the initial and final current conditions at the inductoris = 10mA

is

t = 0

RLiL

1. Initial conditions – assume the current across the inductor is in steady-state.

2. Throw the switch

NB: inductor current cannot change instantaneously

RLiL

DC Transient Response – DC Steady-State

Page 55: ECEN 301Discussion #20 – Exam 2 Review1 DateDayClass No. TitleChaptersHW Due date Lab Due date Exam 10 NovMon20Exam Review LAB 7 EXAM 2 11 NovTue 12 NovWed21Boolean

ECEN 301 Discussion #20 – Exam 2 Review 55

8. find the initial and final current conditions at the inductoris = 10mA

is

t = 0

RLiL

1. Initial conditions – assume the current across the inductor is in steady-state.

2. Throw the switch

NB: inductor current cannot change instantaneously

–R+

LiL

NB: polarity of R

mA

ii LL

10

)0()0(

DC Transient Response – DC Steady-State

Page 56: ECEN 301Discussion #20 – Exam 2 Review1 DateDayClass No. TitleChaptersHW Due date Lab Due date Exam 10 NovMon20Exam Review LAB 7 EXAM 2 11 NovTue 12 NovWed21Boolean

ECEN 301 Discussion #20 – Exam 2 Review 56

8. find the initial and final current conditions at the inductoris = 10mA

is

t = 0

RLiL

1. Initial conditions – assume the current across the inductor is in steady-state.

2. Throw the switch3. Final conditions

NB: in DC steady state inductors act like short circuits

AiL 0)(

DC Transient Response – DC Steady-State

Page 57: ECEN 301Discussion #20 – Exam 2 Review1 DateDayClass No. TitleChaptersHW Due date Lab Due date Exam 10 NovMon20Exam Review LAB 7 EXAM 2 11 NovTue 12 NovWed21Boolean

ECEN 301 Discussion #20 – Exam 2 Review 57

DC Transient ResponseSolving 1st order transient response:

1. Solve the DC steady-state circuit: Initial condition x(0–): before switching (on/off) Final condition x(∞): After any transients have died out (t → ∞)

2. Identify x(0+): the circuit initial conditions Capacitors: vC(0+) = vC(0–) Inductors: iL(0+) = iL(0–)

3. Write a differential equation for the circuit at time t = 0+

Reduce the circuit to its Thévenin or Norton equivalent The energy storage element (capacitor or inductor) is the load

The differential equation will be either in terms of vC(t) or iL(t) Reduce this equation to standard form

4. Solve for the time constant Capacitive circuits: τ = RTC Inductive circuits: τ = L/RT

5. Write the complete response in the form: x(t) = x(∞) + [x(0) - x(∞)]e-t/τ

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ECEN 301 Discussion #20 – Exam 2 Review 58

DC Transient Response9. find vc(t) for all t

vs = 12V, vC(0–) = 5V, R = 1000Ω, C = 470uF

R

Cvs+–

t = 0

i(t)

+vC(t)

Page 59: ECEN 301Discussion #20 – Exam 2 Review1 DateDayClass No. TitleChaptersHW Due date Lab Due date Exam 10 NovMon20Exam Review LAB 7 EXAM 2 11 NovTue 12 NovWed21Boolean

ECEN 301 Discussion #20 – Exam 2 Review 59

9. find vc(t) for all tvs = 12V, vC(0–) = 5V, R = 1000Ω, C = 470uF

V

vv SC

12

)(

R

Cvs+–

t = 0

i(t)

+vC(t)

1. DC steady-statea) Initial condition: vC(0)b) Final condition: vC(∞)

Vvtv CC 5)0()0(

NB: as t → ∞ the capacitor acts like an open circuit thus vC(∞) = vS

DC Transient Response

Page 60: ECEN 301Discussion #20 – Exam 2 Review1 DateDayClass No. TitleChaptersHW Due date Lab Due date Exam 10 NovMon20Exam Review LAB 7 EXAM 2 11 NovTue 12 NovWed21Boolean

ECEN 301 Discussion #20 – Exam 2 Review 60

9. find vc(t) for all tvs = 12V, vC(0–) = 5V, R = 1000Ω, C = 470uF

R

Cvs+–

t = 0

i(t)

+vC(t)

2. Circuit initial conditions: vC(0+)

V

vv CC

5

)0()0(

DC Transient Response

Page 61: ECEN 301Discussion #20 – Exam 2 Review1 DateDayClass No. TitleChaptersHW Due date Lab Due date Exam 10 NovMon20Exam Review LAB 7 EXAM 2 11 NovTue 12 NovWed21Boolean

ECEN 301 Discussion #20 – Exam 2 Review 61

9. find vc(t) for all tvs = 12V, vC(0–) = 5V, R = 1000Ω, C = 470uF

R

Cvs+–

t = 0

i(t)

+vC(t)

3. Write differential equation (already in Thévenin equivalent) at t = 0

SCC

SCC

CRS

vtvdt

tdvRC

vtvRti

tvtvv

)()(

)()(

0)()(

:KVL

DC Transient Response

Page 62: ECEN 301Discussion #20 – Exam 2 Review1 DateDayClass No. TitleChaptersHW Due date Lab Due date Exam 10 NovMon20Exam Review LAB 7 EXAM 2 11 NovTue 12 NovWed21Boolean

ECEN 301 Discussion #20 – Exam 2 Review 62

9. find vc(t) for all tvs = 12V, vC(0–) = 5V, R = 1000Ω, C = 470uF

47.0

)10470)(1000( 6

RC

R

Cvs+–

t = 0

i(t)

+vC(t)

4. Find the time constant τ

1SK

12 SvF

DC Transient Response

Page 63: ECEN 301Discussion #20 – Exam 2 Review1 DateDayClass No. TitleChaptersHW Due date Lab Due date Exam 10 NovMon20Exam Review LAB 7 EXAM 2 11 NovTue 12 NovWed21Boolean

ECEN 301 Discussion #20 – Exam 2 Review 63

9. find vc(t) for all tvs = 12V, vC(0–) = 5V, R = 1000Ω, C = 470uF

R

Cvs+–

t = 0

i(t)

+vC(t)

5. Write the complete responsex(t) = x(∞) + [x(0) - x(∞)]e-t/τ

47.0/

47.0/

/

712

)125(12

)()0()()(

t

t

tCCCC

e

e

evvvtv

DC Transient Response

Page 64: ECEN 301Discussion #20 – Exam 2 Review1 DateDayClass No. TitleChaptersHW Due date Lab Due date Exam 10 NovMon20Exam Review LAB 7 EXAM 2 11 NovTue 12 NovWed21Boolean

ECEN 301 Discussion #20 – Exam 2 Review 64

Frequency Response

Frequency Response H(jω): a measure of how the voltage/current/impedance of a load responds to the voltage/current of a source

)()(

)(jVjV

jHS

LV

)()(

)(jIjI

jHS

LI

)()(

)(jIjV

jHS

LZ

Page 65: ECEN 301Discussion #20 – Exam 2 Review1 DateDayClass No. TitleChaptersHW Due date Lab Due date Exam 10 NovMon20Exam Review LAB 7 EXAM 2 11 NovTue 12 NovWed21Boolean

ECEN 301 Discussion #20 – Exam 2 Review 65

Frequency Response

10. compute the frequency response HV(jω)

R1 = 1kΩ, RL = 10kΩ, C = 10uF

R1

Cvs(t)+–

+RL

Page 66: ECEN 301Discussion #20 – Exam 2 Review1 DateDayClass No. TitleChaptersHW Due date Lab Due date Exam 10 NovMon20Exam Review LAB 7 EXAM 2 11 NovTue 12 NovWed21Boolean

ECEN 301 Discussion #20 – Exam 2 Review 66

Frequency Response

10. compute the frequency response HV(jω)

R1 = 1kΩ, RL = 10kΩ, C = 10uF

R1

Cvs(t)+–

+RL

1. Note frequencies of AC sources

Only one AC source so frequency response HV(jω) will be the function of a single frequency

Page 67: ECEN 301Discussion #20 – Exam 2 Review1 DateDayClass No. TitleChaptersHW Due date Lab Due date Exam 10 NovMon20Exam Review LAB 7 EXAM 2 11 NovTue 12 NovWed21Boolean

ECEN 301 Discussion #20 – Exam 2 Review 67

Frequency Response

10. compute the frequency response HV(jω)

R1 = 1kΩ, RL = 10kΩ, C = 10uF

R1

Cvs(t)+–

+RL

1. Note frequencies of AC sources2. Convert to phasor domain

Z1 = R1

ZLD=RL

ZC=1/jωC

Vs+–~

Page 68: ECEN 301Discussion #20 – Exam 2 Review1 DateDayClass No. TitleChaptersHW Due date Lab Due date Exam 10 NovMon20Exam Review LAB 7 EXAM 2 11 NovTue 12 NovWed21Boolean

ECEN 301 Discussion #20 – Exam 2 Review 68

Frequency Response

10. compute the frequency response HV(jω)

R1 = 1kΩ, RL = 10kΩ, C = 10uF1. Note frequencies of AC sources2. Convert to phasor domain3. Solve using network analysis

• Thévenin equivalent

Z1 = R1

ZC=1/jωC

CT ZZZ ||1

Page 69: ECEN 301Discussion #20 – Exam 2 Review1 DateDayClass No. TitleChaptersHW Due date Lab Due date Exam 10 NovMon20Exam Review LAB 7 EXAM 2 11 NovTue 12 NovWed21Boolean

ECEN 301 Discussion #20 – Exam 2 Review 69

Frequency Response

10. compute the frequency response HV(jω)

R1 = 1kΩ, RL = 10kΩ, C = 10uF

C

CST ZZ

ZjVjV

1

)()(

1. Note frequencies of AC sources2. Convert to phasor domain3. Solve using network analysis

• Thévenin equivalent

Z1 = R1

+VT

ZC=1/jωC

Vs+–~

CT ZZZ ||1

Page 70: ECEN 301Discussion #20 – Exam 2 Review1 DateDayClass No. TitleChaptersHW Due date Lab Due date Exam 10 NovMon20Exam Review LAB 7 EXAM 2 11 NovTue 12 NovWed21Boolean

ECEN 301 Discussion #20 – Exam 2 Review 70

Frequency Response

10. compute the frequency response HV(jω)

R1 = 1kΩ, RL = 10kΩ, C = 10uF

C

CST ZZ

ZjVjV

1

)()(

1. Note frequencies of AC sources2. Convert to phasor domain3. Solve using network analysis

• Thévenin equivalent4. Find an expression for the load voltage

CT ZZZ ||1

ZT

ZLDVT

+–~

+VL

LDC

LD

C

CS

LDT

LDTL

ZZZ

Z

ZZ

ZjV

ZZ

ZjVjV

||)(

)()(

11

Page 71: ECEN 301Discussion #20 – Exam 2 Review1 DateDayClass No. TitleChaptersHW Due date Lab Due date Exam 10 NovMon20Exam Review LAB 7 EXAM 2 11 NovTue 12 NovWed21Boolean

ECEN 301 Discussion #20 – Exam 2 Review 71

Frequency Response

10. compute the frequency response HV(jω)

R1 = 1kΩ, RL = 10kΩ, C = 10uF5. Find an expression for the frequency

response ZT

ZLDVT

+–~

+VL

LDC

LD

C

C

S

LV

ZZZ

Z

ZZ

Z

jV

jVjH

||

)(

)()(

11

Page 72: ECEN 301Discussion #20 – Exam 2 Review1 DateDayClass No. TitleChaptersHW Due date Lab Due date Exam 10 NovMon20Exam Review LAB 7 EXAM 2 11 NovTue 12 NovWed21Boolean

ECEN 301 Discussion #20 – Exam 2 Review 72

Frequency Response

10. compute the frequency response HV(jω)

R1 = 1kΩ, RL = 10kΩ, C = 10uF5. Find an expression for the frequency

response ZT

ZLDVT

+–~

+VL

110arctan

110

100

110

100

)10/(10)10/(11010

)10/(10

||)(

22

53534

54

11

11

j

jj

j

ZZZZZ

ZZ

ZZZ

Z

ZZ

ZjH

CCLD

CLD

LDC

LD

C

CV

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ECEN 301 Discussion #20 – Exam 2 Review 73

Frequency Response

10. compute the frequency response HV(jω)

R1 = 1kΩ, RL = 10kΩ, C = 10uF

2010.0)(

jHV

5. Find an expression for the frequency response• Look at response for low frequencies (ω = 10)

and high frequencies (ω = 10000)

ZT

ZLDVT

+–~

+VL

110arctan

110

100)(

22

jHV

0907.0905.0)( jHV

ω = 10ω = 10000

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ECEN 301 Discussion #20 – Exam 2 Review 74

Basic Filters

Electric circuit filter: attenuates (reduces) or eliminates signals at unwanted frequencies

0.00. 00 10. 00

.

Low-pass

0.00. 00 10. 00

.

High-pass

0.00.00 10.00

.

Band-pass

0.00. 00 10. 00

.

Band-stop

ω ω

ω ω

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ECEN 301 Discussion #20 – Exam 2 Review 75

Basic Filters – Resonant Frequency

Resonant Frequency (ωn): the frequency at which capacitive impedance and inductive impedance are equal and opposite (in 2nd order filters)

LCn

1

C+

vi(t)–

+vo(t)

L

C+

vi(t)–

+vo(t)

–L

Impedances in series Impedances in parallel

Page 76: ECEN 301Discussion #20 – Exam 2 Review1 DateDayClass No. TitleChaptersHW Due date Lab Due date Exam 10 NovMon20Exam Review LAB 7 EXAM 2 11 NovTue 12 NovWed21Boolean

ECEN 301 Discussion #20 – Exam 2 Review 76

Basic Filters – Resonant Frequency

Resonant Frequency (ωn): the frequency at which capacitive impedance and inductive impedance are equal and opposite (in 2nd order filters)

0)( jVo

C

LCjZL

+Vi(jω)

+Vo(jω)

ZEQ=0C

LCjZC

0

CLEQ ZZZ

Impedances in series

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ECEN 301 Discussion #20 – Exam 2 Review 77

Basic Filters – Resonant Frequency

Resonant Frequency (ωn): the frequency at which capacitive impedance and inductive impedance are equal and opposite (in 2nd order filters)

)()( jVjV io

C

LCjZL

+Vi(jω)

+Vo(jω)

ZEQ=∞

C

LCjZC

0

/

||

CL

ZZ

ZZ

ZZZ

CL

CL

CLEQ

Impedances in parallel

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ECEN 301 Discussion #20 – Exam 2 Review 78

Basic Filters – Low-Pass Filters

Low-pass Filters: only allow signals under the cutoff frequency (ω0) to pass

)cos()( 1ttvo

0.00. 00 10. 00

.

Low-pass

ω1 ω0 ω2 ω3

)cos(

)cos(

)cos()(

3

2

1

t

t

ttvi

HL(jω)

R

C+

vi(t)–

+vo(t)

R

C+

vi(t)–

+vo(t)

L

1st Order

2nd Order

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ECEN 301 Discussion #20 – Exam 2 Review 79

Basic Filters – High-Pass Filters

High-pass Filters: only allow signals above the cutoff frequency (ω0) to pass

)cos()( 3ttvo )cos(

)cos(

)cos()(

3

2

1

t

t

ttvi

HH(jω)

0.00. 00 10. 00

.

High-pass

ω1 ω0ω2 ω3

+vi(t)

+vo(t)

1st Order

RC

R

+vi(t)

+vo(t)

2nd Order

C L

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ECEN 301 Discussion #20 – Exam 2 Review 80

Basic Filters – Band-Pass Filters

Band-pass Filters: only allow signals between the passband (ωa to ωb) to pass

)cos()( 2ttvo )cos(

)cos(

)cos()(

3

2

1

t

t

ttvi

HB(jω)

0.00.00 10.00

.

Band-pass

ω1 ωa ω2 ω3ωb

+vi(t)

+vo(t)

2nd Order

RC

L

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ECEN 301 Discussion #20 – Exam 2 Review 81

Basic Filters – Band-Stop Filters

Band-stop Filters: allow signals except those between the stopband (ωa to ωb) to pass

)cos(

)cos()(

3

1

t

ttvo

)cos(

)cos(

)cos()(

3

2

1

t

t

ttvi

HN(jω)

+vi(t)

+vo(t)

2nd Order

RC

L

0.00. 00 10. 00

.

Band-stop

ω1 ωa ω2 ω3ωb

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ECEN 301 Discussion #20 – Exam 2 Review 82

Op-Amps – Open-Loop ModeOpen-Loop Model: an ideal op-amp acts like a difference amplifier (a

device that amplifies the difference between two input voltages)

++

v+

+

v–

+

vo

io

i2

i1

–vin

+

+

+–

RoutRin

i1

AOLvin

+

vo

vin

+

v–

v+

NB: op-amps have near-infinite input resistance (Rin) and very small output resistance (Rout)

)(

vvA

vAv

OL

inOLoAOL – open-loop voltage gain

Page 83: ECEN 301Discussion #20 – Exam 2 Review1 DateDayClass No. TitleChaptersHW Due date Lab Due date Exam 10 NovMon20Exam Review LAB 7 EXAM 2 11 NovTue 12 NovWed21Boolean

ECEN 301 Discussion #20 – Exam 2 Review 83

Op-Amps – Closed-Loop Mode

Circuit Diagram ACL

Inverting Amplifier

Summing Amplifier

N

nSn

n

F

N

nSnOLno

vR

R

vAv

1

1

+ +vo

+–

vS

RS

RF

SS

F

SCLo

vRR

vAv

+ +vo

+–

+–

+–

RSn

RS2

RS1

vSn

vS2

vS1

RF

Page 84: ECEN 301Discussion #20 – Exam 2 Review1 DateDayClass No. TitleChaptersHW Due date Lab Due date Exam 10 NovMon20Exam Review LAB 7 EXAM 2 11 NovTue 12 NovWed21Boolean

ECEN 301 Discussion #20 – Exam 2 Review 84

Op-Amps – Closed-Loop Mode

Circuit Diagram ACL

Noninverting Amplifier

Voltage Follower

s

sCLo

v

vAv

SS

F

SCLo

vR

R

vAv

1

+ +vo

+–

R

RS

RF

vS

+ +vo

+–

Page 85: ECEN 301Discussion #20 – Exam 2 Review1 DateDayClass No. TitleChaptersHW Due date Lab Due date Exam 10 NovMon20Exam Review LAB 7 EXAM 2 11 NovTue 12 NovWed21Boolean

ECEN 301 Discussion #20 – Exam 2 Review 85

Op-Amps – Closed-Loop Mode

Circuit Diagram ACL

Differential Amplifier

12 SSS

Fo vv

R

Rv

–+ +

vo

+–

+–

RS

RS

RF

RF

v1

v2

Page 86: ECEN 301Discussion #20 – Exam 2 Review1 DateDayClass No. TitleChaptersHW Due date Lab Due date Exam 10 NovMon20Exam Review LAB 7 EXAM 2 11 NovTue 12 NovWed21Boolean

ECEN 301 Discussion #20 – Exam 2 Review 86

Op-Amps – Closed-Loop Mode

Circuit Diagram ACL

Ideal Integrator

Ideal Differentiator

dt

tdvCRv SSFo

)(

t

SFS

o dvCR

v )(1

+ +vo(t)

+–

vS

CS

RF

+ +vo(t)

+–

vS

RS

CF

Page 87: ECEN 301Discussion #20 – Exam 2 Review1 DateDayClass No. TitleChaptersHW Due date Lab Due date Exam 10 NovMon20Exam Review LAB 7 EXAM 2 11 NovTue 12 NovWed21Boolean

ECEN 301 Discussion #20 – Exam 2 Review 87

Op-Amps

11. find an expression for the gainCF = 1/6 F, R1 = 3Ω, R2 = 2Ω, CS = 1/6 F

+

vo(t)iin

CF

R2 v+

v–

iF(t)

i2(t)

R1

i1(t) CS

iS(t)

vs(t)

Page 88: ECEN 301Discussion #20 – Exam 2 Review1 DateDayClass No. TitleChaptersHW Due date Lab Due date Exam 10 NovMon20Exam Review LAB 7 EXAM 2 11 NovTue 12 NovWed21Boolean

ECEN 301 Discussion #20 – Exam 2 Review 88

Op-Amps

11. find an expression for the gainCF = 1/6 F, R1 = 3Ω, R2 = 2Ω, CS = 1/6 F

+

Vo(jω)Iin

ZF=1/jωCF

Z2 v+

v–

IF(jω)

I2(jω)

Z1

I1(jω)ZS

IS(jω)

Vs(jω)

Node a

Node b

3

1

62

1

2

1

63

1

111111

0

0

:aat KCL

1221

21

21

Soa

SF

oF

a

oa

F

aoaS

F

Vj

Vj

V

ZV

ZZV

ZZZV

Z

VV

Z

VV

Z

VV

III

1. Transfer to frequency domain2. Apply KCL at nodes a and b

NB: v+ = v– and Iin = 0

Page 89: ECEN 301Discussion #20 – Exam 2 Review1 DateDayClass No. TitleChaptersHW Due date Lab Due date Exam 10 NovMon20Exam Review LAB 7 EXAM 2 11 NovTue 12 NovWed21Boolean

ECEN 301 Discussion #20 – Exam 2 Review 89

Op-Amps

11. find an expression for the gainCF = 1/6 F, R1 = 3Ω, R2 = 2Ω, CS = 1/6 F

+

Vo(jω)Iin

ZF=1/jωCF

Z2 v+

v–

IF(jω)

I2(jω)

Z1

I1(jω)ZS

IS(jω)

Vs(jω)

Node a

Node b

02

1

62

1

0111

00

0

:bat KCL

22

2

2

jVV

ZZV

ZV

Z

V

Z

VV

III

oa

Soa

S

ooa

inS

1. Transfer to frequency domain2. Apply KCL at nodes a and b

Page 90: ECEN 301Discussion #20 – Exam 2 Review1 DateDayClass No. TitleChaptersHW Due date Lab Due date Exam 10 NovMon20Exam Review LAB 7 EXAM 2 11 NovTue 12 NovWed21Boolean

ECEN 301 Discussion #20 – Exam 2 Review 90

Op-Amps

11. find an expression for the gain

CF = 1/6 F, R1 = 3Ω, R2 = 2Ω, CS = 1/6 F

033 jVV oa

+

Vo(jω)Iin

ZF=1/jωCF

Z2 v+

v–

IF(jω)

I2(jω)

Z1

I1(jω)ZS

IS(jω)

Vs(jω)

1. Transfer to frequency domain2. Apply KCL at nodes a and b3. Express Vo in terms of Vs

Soa VjVjV 235

65

62

j

VV So

Page 91: ECEN 301Discussion #20 – Exam 2 Review1 DateDayClass No. TitleChaptersHW Due date Lab Due date Exam 10 NovMon20Exam Review LAB 7 EXAM 2 11 NovTue 12 NovWed21Boolean

ECEN 301 Discussion #20 – Exam 2 Review 91

Op-Amps

11. find an expression for the gain

CF = 1/6 F, R1 = 3Ω, R2 = 2Ω, CS = 1/6 F

+

Vo(jω)Iin

ZF=1/jωCF

Z2 v+

v–

IF(jω)

I2(jω)

Z1

I1(jω)ZS

IS(jω)

Vs(jω)

1. Transfer to frequency domain2. Apply KCL at nodes a and b3. Express Vo in terms of VS

4. Find the gain (Vo/VS)

65

62

jV

V

S

o