Syllabus

• 이론강의 + 실험

• 주교재

– 전기전자공학개론, Giorgio Rizzoni (송재복 외 역), McGraw-Hill Korea, 5판

• 부교재

– 전기전자공학의 길라잡이, 신윤기, GS인터비젼, 2014년

– 기초전기전자공학, T. L. Floyd, D. M. Buchla (손상희 외 역), 시그마프레스, 8판

• 성적

– 이론강의 수업태도(출석, 숙제 등 10%) + 중간고사(30%) + 기말고사(25%) + 실험보고서(20%) + Term project (15%)

– 실험 출석 별도

– 교수별 분반 합산하여 성적 산출

주 이론강의 실험 참고

1 오리엔테이션 실험조 편성

2 저항회로망 해석 전원공급기/디지털 멀티미터

3 등가회로 등가회로/중첩의 원리/최대전력전달

4 선형회로 시간응답 함수발생기/오실로스코프

5 휴강 휴강 추석연휴

6 선형회로 주파수응답 RLC회로

7 다이오드 및 정류회로 다이오드/광소자/정류회로

8 중간고사 중간고사 중간고사

9 트랜지스터 트랜지스터 특성실험

10 연산증폭기 원리/응용 연산증폭기 특성/응용 실험

11 디지털 논리회로 디지털 논리회로 실험

12 조합/순차논리회로 Flip-flop, 카운터 실험 TP 계획서/부품신청

13 Term project 수행 Term project 수행 보강

14 Term project 수행/발표 Term project 수행/발표 보강

15 Term project 발표 Term project 발표 보강

16 기말고사 기말고사 기말고사

DC CIRCUITS

Ho Kyung Kim, Ph.D.

hokyung@pusan.ac.kr

School of Mechanical Engineering

Pusan National University

Basic Experiment and Design of Electronics

Outline

• Definition

• Serial vs. parallel circuits with resistances

• Kirchhoff’s law

• Voltage divider

• Loading effect

• Measuring devices

• Circuit analysis

Analogy btwn fluid & electricity

v

q R

i

Ground

h

Q

Q

R

Ground

• Charge: fundamental electronic quantity

– elementary charges: electron, proton

– electronic charge, q = 1.602 10-19 C

• Current: C/s or A

• Voltage or potential difference: 1 V = 1 J/C

• Ground: earth ground/chassis ground

• Power: J/s or W

• Source (energy generation) vs. load (energy dissipation)

– battery vs. a light bulb

Definition

dt

dqi

CurrentVoltageTime

Charge

Charge

Work

Time

WorkPower

R

VRIVIP

22

• Circuit or network

• Source

– voltage

– current: DC vs. AC

• Branch

• Node

• Loop Mesh

• Network analysis

– to determine a specific voltage, current, or power somewhere in a network

• Resistance: constant of proportionality between the voltage and current

• Ohm's law

Resistor

A

l

r

v

iv

1/Ri

RIV

A

l

A

l

I

VR

r r = resistivity [Wcm]

= 1/r = conductivity [(Wcm)-1 or S/cm]

– Electron drift velocity

– Current

– Conductance

l

VEv eee

Vl

AV

l

Aqn

l

VAqnnvqAI eee )(

RG

1 [S or mho] GVI

– Algebraic sum of the currents leaving a node is zero

– Sum of currents entering node is equal to the sum of the currents leaving the node

– Charge conservation law

• Algebraic sum of the currents entering any node is zero;

KCL: Kirchhoff's current law

0)(1

N

j

j ti

i1(t)

i5(t)

i4(t)

i3(t)

i2(t)

0)()()()()( 54321 tititititi

0)()()()()( 54321 tititititi

)()()()()( 43251 tititititi

• Algebraic sum of the voltages around any loop is zero;

– energy conservation law

KVL: Kirchhoff's voltage law

0)(1

N

j

j tv

+–

+ -

+

-

+-

SV

1RV

2RV

3RV

0321 RRRS VVVV

• Series circuit

– Two or more circuit elements are said to be in series if the current from one element exclusively flows into the next element

– From KCL, it then follows that all series elements have the same current

• Parallel circuit

– Two or more circuit elements are said to be in parallel if the elements share the same terminals

– From KVL, it follows that the parallel elements will have the same voltage

Series vs. parallel circuits

Series circuit

–+

+–

+ –

– +

–+

+ -

)(1 tv

1Rv

2Rv

1R

+

-2R)(5 tv

)(2 tv

)(3 tv

)(4 tv

)(ti

0)()()()()()()( 1542321 tvtvtvtiRtvtvtiR

)()()()()()( 5432121 tvtvtvtvtvtiRR

+–

)(tv

1R

2R

)(ti

≡ v(t)

sum of several voltage sources in series can be replaced by one sourcewhose value is the algebraic sum of the individual sources

+–

)(tv SR

)(ti

≡ RS

equivalent resistance of N resistors in seriesis simply the sum of the individual resistances

N

j

jS RR1

Parallel circuit

1R 2R)(1 ti↑ ↓ ↑ ↓)(tv+

-

)(3 ti )(4 ti )(6 ti

)(2 ti )(5 ti

0)()()()()()( 654321 titititititi

)()()()()()( 526431 titititititi

↑)(0 ti 1R 2R )(tv+

-

sum of several current sources in parallel can be replaced by one source whose value is the algebraic sum of the individual sources

≡ i0(t)

)(11

21

tvRR

↑ PR)(0 ti )(tv+

-

N

j jP RR 1

11

PR

tv )(

Voltage divider

+

-)(tv

1Rv

2Rv

1R

+–

+

-2R

)(ti KVL; 0)( 21 RR vvtv

21)( RR vvtv

Ohm's law; )(11 tiRvR

)(22 tiRvR

Therefore,

)()()( 21 tiRtiRtv

21

)()(

RR

tvti

)()(21

111 tv

RR

RtiRvR

)()(21

222 tv

RR

RtiRvR

v(t) is divided between R1 and R2 in direct proportion to their resistances; voltage divider

• Voltage divider: the voltage across each resistor in a series circuit is directly proportional to the ratio of its resistance to the total resistance of the circuit

Divider rules

• Current divider: the current in a parallel circuit divides in inverse proportion to the resistances of the individual parallel elements

S

Nn

nn i

RRRR

Ri

/1/1/1/1

/1

21

S

Nn

nn v

RRRR

Rv

21

Loading effect

+–Vin = 30 V

R1 = 10 k

R2 = 10 k

Vout = ?

Vin

R1

R2

Vout

R3

Vin

R1

R2 R3

Vin

R1

R2 || R3

Vout

• Ammeter

– current measuring device

– connected in series for the same current

– zero internal resistance required

• Voltmeter

– voltage measuring device

– connected in parallel for the same voltage

– infinite internal resistance required

• Ohmmeter

– resistance measuring device

– connected and functioned when the element is disconnected from any other circuit

Ohmmeter

Measuring devices

R

Ammeter

Voltmeter

Open and short circuits

V

+

-

I

V

+

-

I

I = 0 for any VR =

V = 0 for any IR = 0

• Or network analysis

• To determine a specific voltage, current, or power somewhere in a network

• Two methods

– Nodal analysis = node voltage method

– Loop analysis = mesh current method

Circuit analysis

Nodal analysis

• or node voltage method

① select a reference node (usually ground)

② define n – 1 node voltages

③ determine branch currents using Ohm's law

④ apply KCL at each node

⑤ solve the linear system

– n – 1 – m unknowns if m voltage sources

① select a reference node

② define n – 1 node voltages

11

1R

v

R

vvi aca

2

2R

vvi ba

33

3R

v

R

vvi bcb

③ determine branch currents

④ apply KCL at each node

⑤ solve the linear system

021 iiiS 032 ii

Sba ivR

vRR

221

1110

111

322

ba v

RRv

R

• or mesh current method

① define each mesh current consistently

– e.g., clockwise direction

② apply KVL at each mesh

③ solve the linear system

– n – m unknowns if m current sources

Loop analysis

① define each mesh current

② apply KVL at each mesh

③ solve the linear system

0)( 22111 RiiRivS

0)( 4232212 RiRiRii

SviRiRR 22121 )(

0)( 243212 iRRRiR