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7. Magnetostatic Field

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Page 1: 7. Magnetostatic Fieldiirc.khu.ac.kr/uploads/6/3/4/3/63434825/sadiku_ch07.pdf · 2019-11-23 · 12 2013. 1 학기기말고사: J =(x,0,0)일때중심이원점에있고반지름이a인구의표면을통과하여

7. Magnetostatic Field

Page 2: 7. Magnetostatic Fieldiirc.khu.ac.kr/uploads/6/3/4/3/63434825/sadiku_ch07.pdf · 2019-11-23 · 12 2013. 1 학기기말고사: J =(x,0,0)일때중심이원점에있고반지름이a인구의표면을통과하여

1

Matrix, Cross Product, Determinant

4 0 10

14

132

212

102

a)BABA(

a)BABA(

a)BABA(

BBB

AAA

aaa

BA

)B,B,B(B

)A,A,A(A

zxyyx

yxzzx

xyzzy

zyx

zyx

zyx

zyx

zyx

Page 3: 7. Magnetostatic Fieldiirc.khu.ac.kr/uploads/6/3/4/3/63434825/sadiku_ch07.pdf · 2019-11-23 · 12 2013. 1 학기기말고사: J =(x,0,0)일때중심이원점에있고반지름이a인구의표면을통과하여

2

22

22

2

2

2

yx3

]x)yx[(xx

f

?x

f

x)z,y,x(f

xy2x

f

zyx)z,y,x(f

)8.2(

zz

siny

cosx

)7.2(

zz

x

ytan

yx

1

22

φ

z

x

y

z

ρ

az

ρdφ

dz

편미분 (Partial Derivative)

Page 4: 7. Magnetostatic Fieldiirc.khu.ac.kr/uploads/6/3/4/3/63434825/sadiku_ch07.pdf · 2019-11-23 · 12 2013. 1 학기기말고사: J =(x,0,0)일때중심이원점에있고반지름이a인구의표면을통과하여

3

)Spherical(A

sinr

1)sinA(

sinr

1)Ar(

rr

1A

)lCylindrica( z

AA1)A(

1A

(Catesian) z

A

y

A

x

AA

Divergence

)Spherical( aV

sinr

1a

V

r

1a

r

VV

)lCylindrica( az

Va

V1a

VV

)(Cartesian az

Va

y

Va

x

VV

Gradient

r2

2

z

zyx

r

z

zyx

Del Operator

Page 5: 7. Magnetostatic Fieldiirc.khu.ac.kr/uploads/6/3/4/3/63434825/sadiku_ch07.pdf · 2019-11-23 · 12 2013. 1 학기기말고사: J =(x,0,0)일때중심이원점에있고반지름이a인구의표면을통과하여

4

AsinrrAAr

asinrara

sinr

1A

AAAz

aaa

1A

AAA

zyx

aaa

A

Curl

r

r

2

z

z

zyx

zyx

zxyyx

yxzzx

xyzzy

zyx

zyx

zyx

a)BABA(

a)BABA(

a)BABA(

BBB

AAA

aaa

BA

Page 6: 7. Magnetostatic Fieldiirc.khu.ac.kr/uploads/6/3/4/3/63434825/sadiku_ch07.pdf · 2019-11-23 · 12 2013. 1 학기기말고사: J =(x,0,0)일때중심이원점에있고반지름이a인구의표면을통과하여

5dzddxddv

add

adzd

adzdSd

adzadadLd

coordinate ylindricalC

dzdxdyxddv

adS

adydx

adxdz

adzdy Sd

adzadyadxLd

coordinateCartesian

3

z

z

3

n

z

y

x

zyx

적분자 (Integrator)

φ

z

x

y

z

ρ

az

ρdφ

dz

dL dzaz

dxax

dyay

Page 7: 7. Magnetostatic Fieldiirc.khu.ac.kr/uploads/6/3/4/3/63434825/sadiku_ch07.pdf · 2019-11-23 · 12 2013. 1 학기기말고사: J =(x,0,0)일때중심이원점에있고반지름이a인구의표면을통과하여

6

ddrdsinrxddv

addr

addrsinr

addsinrSd

adsinrardadrLd

coordinate Spherical

23

r2

r

θ는 Zenith Angle이고φ는Azimuthal Angle.

φ

z

x

y

θ

rdφ

r

dr

r sinθdφ

rdθr sinθ

Page 8: 7. Magnetostatic Fieldiirc.khu.ac.kr/uploads/6/3/4/3/63434825/sadiku_ch07.pdf · 2019-11-23 · 12 2013. 1 학기기말고사: J =(x,0,0)일때중심이원점에있고반지름이a인구의표면을통과하여

7

v3

vS

S nL

xdAdvASdA

theorem)(Gauss theoremDivergence

Sda)A(LdA

theoremsStoke'

선적분, 면적분

Page 9: 7. Magnetostatic Fieldiirc.khu.ac.kr/uploads/6/3/4/3/63434825/sadiku_ch07.pdf · 2019-11-23 · 12 2013. 1 학기기말고사: J =(x,0,0)일때중심이원점에있고반지름이a인구의표면을통과하여

8

densitychargeVolume:

densityCurrent:J

)(ty Permittivi : m/F10854.8m/F36/10

)(tyPermeabili:m/H104

fieldElectric:E

densityfluxElectric:ED

fluxMagnetic:B

fieldMagnetic:/BH

EqAmperet

DJH

VE0EEqFaradayt

BE

EqGauss0B

EqGaussD

v

1290

70

v

유전율

투자율

Maxwell Equation

Page 10: 7. Magnetostatic Fieldiirc.khu.ac.kr/uploads/6/3/4/3/63434825/sadiku_ch07.pdf · 2019-11-23 · 12 2013. 1 학기기말고사: J =(x,0,0)일때중심이원점에있고반지름이a인구의표면을통과하여

9

Ex 3.7 G r = 10e−z(ρaρ + az)일때 ρ=1, 0 ≤ z ≤1 인원통밖으로

나오는 G의 Flux를구하라.

0

2

1102)e1(102

2

12e10

dd10dzde10dde10

)0z(dd)a()aa(e10

)1(dzda)aa(e10

)1z(dda)aa(e10

dSaG

11

1

0

2

0

1

0

2

0z1

0

2

01

b1

0

2

0 zzz

s1

0

2

0 zz

t1

0

2

0 zzz

bstS n

zadd

adzd

adzdSd

coordlCylindrica

Ψt

Ψs

Ψb

z

yx

Page 11: 7. Magnetostatic Fieldiirc.khu.ac.kr/uploads/6/3/4/3/63434825/sadiku_ch07.pdf · 2019-11-23 · 12 2013. 1 학기기말고사: J =(x,0,0)일때중심이원점에있고반지름이a인구의표면을통과하여

10

2014.1 학기 중간고사:

다음그림의 Closed Path에서 (zax + yay + yaz) ∙ dL 을구하라.

xy

z1

1

2

1

0)adzLd,0yx(

Ld)ayayaz(

02

11

2

1dz)z1(dy)y(

)adzadyLd,0x,y1z(

Ld)ayayaz(

2/1dy)y()adyLd,0zx(

Ld)ayayaz(

Ld)ayayaz(

z

3 zyx

1

0

0

1

zy

2 zyx

1

0y

1 zyx

L zyx

zyx adzadyadxLd

coordCartesian

dL dzaz

dxax

dyay

Page 12: 7. Magnetostatic Fieldiirc.khu.ac.kr/uploads/6/3/4/3/63434825/sadiku_ch07.pdf · 2019-11-23 · 12 2013. 1 학기기말고사: J =(x,0,0)일때중심이원점에있고반지름이a인구의표면을통과하여

11

2013. 1 학기 기말고사:

J = (x, 0,0)일때중심이원점에있고반지름이 a인구의표면을통과하여흐르는전류의양을구하라.

3

3

3

3zyx

3

n

a3

4

xd

xdz

0

y

0

x

x

xdz

J

y

J

x

J

xdJ

dSaJ

a

dS

an=ar

Page 13: 7. Magnetostatic Fieldiirc.khu.ac.kr/uploads/6/3/4/3/63434825/sadiku_ch07.pdf · 2019-11-23 · 12 2013. 1 학기기말고사: J =(x,0,0)일때중심이원점에있고반지름이a인구의표면을통과하여

12

2013. 1 학기 기말고사:

J = (x, 0,0)일때중심이원점에있고반지름이 a인구의표면을통과하여흐르는전류의양을구하라.

3

3

2

0

1

023

2

02

033

2

rx

n

a3

4

)(3

2a2

d2

)2cos(1dt)t1(a2

tcos

dcosdsina

)ddsinr)(cos)(sincossinr(

dSaax

dSaJ

)23.2(

asinacosa

acos

asincos

asinsina

asin

acoscos

acossina

)22.2(

cosrz

sinsinry

cossinrx

rz

ry

rx

addraddrsinraddsinrSd

coordinate Spherical

r2

Page 14: 7. Magnetostatic Fieldiirc.khu.ac.kr/uploads/6/3/4/3/63434825/sadiku_ch07.pdf · 2019-11-23 · 12 2013. 1 학기기말고사: J =(x,0,0)일때중심이원점에있고반지름이a인구의표면을통과하여

13

tan 1 cot

sin cos

cscsec

2

22

secd

tand

sind

cosd

cosd

sind

tantan1

tantan)tan(

sincos)2cos(

sinsincoscos)cos(

cossin2)2sin(

sincoscossin)sin(

Page 15: 7. Magnetostatic Fieldiirc.khu.ac.kr/uploads/6/3/4/3/63434825/sadiku_ch07.pdf · 2019-11-23 · 12 2013. 1 학기기말고사: J =(x,0,0)일때중심이원점에있고반지름이a인구의표면을통과하여

14ab

h1

b

1

a

1

ba

h1

zh

bab

ba

h1

dzzh

bab

1

zh

bab

dz1

dzz

S

LR

h/z)ba(b

h

0

1

h

0

2

h

0 2

h

0 22

2013. 1학기 기말고사:

전도율이 σ 인물질로만들어진다음그림의원뿔대의상하양단사이의저항R을구하라.

Δz ~ dzρ

a

b

hz

ρ

Page 16: 7. Magnetostatic Fieldiirc.khu.ac.kr/uploads/6/3/4/3/63434825/sadiku_ch07.pdf · 2019-11-23 · 12 2013. 1 학기기말고사: J =(x,0,0)일때중심이원점에있고반지름이a인구의표면을통과하여

15JA/VeqPoisson

2/HBw2/EDwdensityEnergy

dt/LdIVdt/CdVI

LICVQ

SdBSdDFlux

r4

LIdA

r4

dLVPotential

)0J(VHVEPotential

HBEDField

]m/Wb[S/B]m/C[S/DdensityFlux

]m/A[L/IH]m/volt[L/VEensityintField

LIdvQdQelementSource

BvQFEQFForce

ILdHQSdD

R4

aLIdBda

r4

QQFlawBasic

2v

2

mE

L

m

22

encenc

2r0

r221

관계

자장전장

표 7.1 전기장과 자기장의 상사성

t

DJH

t

BE

0B

D v

Maxwell

Page 17: 7. Magnetostatic Fieldiirc.khu.ac.kr/uploads/6/3/4/3/63434825/sadiku_ch07.pdf · 2019-11-23 · 12 2013. 1 학기기말고사: J =(x,0,0)일때중심이원점에있고반지름이a인구의표면을통과하여

16

7.2 BIOT-SAVART’S LAW

)4.7(R4

RLdI

R4

aLdIHd

)3.7(R4

sindLIdH

)2.7(R

sindLkIdH

)1.7(R

sindLIdH

32R

2

2

2

Fig 7.1 𝐈𝐝 𝐋에 의한 자기장 𝐝𝐇

𝐁~𝐇

𝐑

𝐝 𝐋 I

P

𝛂

Page 18: 7. Magnetostatic Fieldiirc.khu.ac.kr/uploads/6/3/4/3/63434825/sadiku_ch07.pdf · 2019-11-23 · 12 2013. 1 학기기말고사: J =(x,0,0)일때중심이원점에있고반지름이a인구의표면을통과하여

17

Fig 7.2 Determining of dH using

(a) the right-hand rule, or

(b) the right=handed screw rule.

H (or I) is out

(a)

H (or I) is in

(b)

Fig 7.3 Conventional representation

of H (or I)

Page 19: 7. Magnetostatic Fieldiirc.khu.ac.kr/uploads/6/3/4/3/63434825/sadiku_ch07.pdf · 2019-11-23 · 12 2013. 1 학기기말고사: J =(x,0,0)일때중심이원점에있고반지름이a인구의표면을통과하여

18

Page 20: 7. Magnetostatic Fieldiirc.khu.ac.kr/uploads/6/3/4/3/63434825/sadiku_ch07.pdf · 2019-11-23 · 12 2013. 1 학기기말고사: J =(x,0,0)일때중심이원점에있고반지름이a인구의표면을통과하여

19

J

Ld

dvJ

LdAJ

LdAJLId

J

na

A

K

a

1

IdL = K ∙ adL

= Ka ∙ dL

= KdS

dL

an

Page 21: 7. Magnetostatic Fieldiirc.khu.ac.kr/uploads/6/3/4/3/63434825/sadiku_ch07.pdf · 2019-11-23 · 12 2013. 1 학기기말고사: J =(x,0,0)일때중심이원점에있고반지름이a인구의표면을통과하여

20

𝐁

𝐑~𝐚𝐫

𝐝 𝐋 I

P

(7.8)current) (volume R4

advJH

(7.7)current) (surface R4

adSKH

(7.6)current) (line R4

aLdIH

)5.7( dvJdSKdLI

R4

RLdI

R4

aLdIHd)4.7(

V 2R

S 2R

L 2R

32R

Page 22: 7. Magnetostatic Fieldiirc.khu.ac.kr/uploads/6/3/4/3/63434825/sadiku_ch07.pdf · 2019-11-23 · 12 2013. 1 학기기말고사: J =(x,0,0)일때중심이원점에있고반지름이a인구의표면을통과하여

21

Line current

z

xy

Ld

R a

z

x y

aza

a

z

B

O

α2

α1

RI

H

ρ

d L

aφP

)11.7( a]z[4

dzIH

)10.7(adz)aza(adzRLd

)9.7( R4

RLIdHd

2/322

zz

3

Page 23: 7. Magnetostatic Fieldiirc.khu.ac.kr/uploads/6/3/4/3/63434825/sadiku_ch07.pdf · 2019-11-23 · 12 2013. 1 학기기말고사: J =(x,0,0)일때중심이원점에있고반지름이a인구의표면을통과하여

22

z

B

O

α2

α1

RI

H

ρ

aρd L = aLdL

aφP

Fig 7.5 직선선도체에의한 P 점의자기장

)12.7(a)cos(cos4

IH

a)cos(cos4

I

dsin4

aI

accs

dccs

4

I

dccsdz

cotz

)11.7(a]z[4

dzIH

12

12

33

22

2

2/322

2

1

2

1

dccsdz

sin

sin

coscossinsin

d

dz

sin

cos

tan

1z

cotz

2

2

2

Page 24: 7. Magnetostatic Fieldiirc.khu.ac.kr/uploads/6/3/4/3/63434825/sadiku_ch07.pdf · 2019-11-23 · 12 2013. 1 학기기말고사: J =(x,0,0)일때중심이원점에있고반지름이a인구의표면을통과하여

23

dccs

tan

dsec

tan

tan

dseczdz

0d

dsecztandz)tanz(d

tanz

dccsdz

cotz

2

2

2

2

2tan 1 cot

sin cos

cscsec

2

22

secd

tand

sind

cosd

cosd

sind

tantan1

tantan)tan(

sincos)2cos(

sinsincoscos)cos(

cossin2)2sin(

sincoscossin)sin(

Page 25: 7. Magnetostatic Fieldiirc.khu.ac.kr/uploads/6/3/4/3/63434825/sadiku_ch07.pdf · 2019-11-23 · 12 2013. 1 학기기말고사: J =(x,0,0)일때중심이원점에있고반지름이a인구의표면을통과하여

24

z

B

O

α2

α1

RI

H

ρ

aρd L = aLdL

aφP

Fig 7.5 직선 선도체에의한 P 점의 자기장

)15.7( aaa

0,

current line infinitefor )14.7(a

2

IH

0,2/

current line infinite-semifor )13.7(a

4

IH

a)cos(cos4

IH)12.7(

L

21

21

12

Page 26: 7. Magnetostatic Fieldiirc.khu.ac.kr/uploads/6/3/4/3/63434825/sadiku_ch07.pdf · 2019-11-23 · 12 2013. 1 학기기말고사: J =(x,0,0)일때중심이원점에있고반지름이a인구의표면을통과하여

25

예제 7.1 그림 7.6 과 같이 도체 Loop에 10 A 의 전류가 흐를 때 (0,0,5)에서

(1) 번 도선에 의한 𝐇 를 구하라.

x

z5

2

2

1)5,0,0(

1

그림 7.6 삼각형도체 Loop

1

1 2x

z

y

10 A

(0,0,5)

(a)

m/mAa1.59

)a)(029/2(54

10H

)cos(cos4

IH

a)cos(cos4

IH)12.7(

29

2

25

2cos

0cos

2/

5

y

y

12

12

222

1

1

Page 27: 7. Magnetostatic Fieldiirc.khu.ac.kr/uploads/6/3/4/3/63434825/sadiku_ch07.pdf · 2019-11-23 · 12 2013. 1 학기기말고사: J =(x,0,0)일때중심이원점에있고반지름이a인구의표면을통과하여

26

m/mAa65.28a2.38

)a5

3a

5

4)(01(

54

3H

)cos(cos4

IH)12.7(

yx

yx

12

yx a5

3a

5

4

예제 7.2 그림 7.7 에서 보여준 3 A 가 흐르는 도선전류에 의한

(3,4,0)에서의 𝐇 를 구하라.

1cos

0cos

5

2

1

(𝟏) 𝐇𝟏

Page 28: 7. Magnetostatic Fieldiirc.khu.ac.kr/uploads/6/3/4/3/63434825/sadiku_ch07.pdf · 2019-11-23 · 12 2013. 1 학기기말고사: J =(x,0,0)일때중심이원점에있고반지름이a인구의표면을통과하여

27

m/mAa88.23

a)5

31(

44

3H

)cos(cos4

IH)12.7(

z

z

12

za

m/mA)88.23,65.28,2.38(

HHH 21

1cos

5/3cos

4

2

1

(𝟐) 𝐇𝟐

Page 29: 7. Magnetostatic Fieldiirc.khu.ac.kr/uploads/6/3/4/3/63434825/sadiku_ch07.pdf · 2019-11-23 · 12 2013. 1 학기기말고사: J =(x,0,0)일때중심이원점에있고반지름이a인구의표면을통과하여

28

Page 30: 7. Magnetostatic Fieldiirc.khu.ac.kr/uploads/6/3/4/3/63434825/sadiku_ch07.pdf · 2019-11-23 · 12 2013. 1 학기기말고사: J =(x,0,0)일때중심이원점에있고반지름이a인구의표면을통과하여

29

예제 7.3 그림 7.8 (a)에서 𝐚φ 방향으로 10 A 의 전류가 흐른다. (0,0,4)와

(0,0,-4)에서 𝐇 를 구하라. Coil의 반경은 3 이다.

Fig 7.8 (a) circular current loop,

(b) flux lines due to the current loop.

x

y

z

dHz

dHρ

dL aρ

ρ𝜑

R

P(0,0,h)

I

(a) circular current loop. (b) flux lines due to the current loop.

𝐇

𝐈

Page 31: 7. Magnetostatic Fieldiirc.khu.ac.kr/uploads/6/3/4/3/63434825/sadiku_ch07.pdf · 2019-11-23 · 12 2013. 1 학기기말고사: J =(x,0,0)일때중심이원점에있고반지름이a인구의표면을통과하여

30

m/A)36.0,0,0()4,0,0(H

m/A)36.0,0,0()4,0,0(H

)h(2

aI

)h(4

a2I

)h(4

a2I

)h(4

d)asina(coshIH

)adahd()h(4

IHd

adahd

h0

0d0

aaa

RLd

aha

)0,y,x()h,0,0(R

adLd

R4

RLIdHd)9.7(

2/322z

2

2/322z

2

2/322z

22

0 2/322

yx

z2

2/322

z2

z

z

3

x

y

z

dHz

dHρ

dL aρ

ρ𝜑

R

P(0,0,h)

I

yx

z

asinacosa)10.2(

adzadadLd)5.3(

Page 32: 7. Magnetostatic Fieldiirc.khu.ac.kr/uploads/6/3/4/3/63434825/sadiku_ch07.pdf · 2019-11-23 · 12 2013. 1 학기기말고사: J =(x,0,0)일때중심이원점에있고반지름이a인구의표면을통과하여

31

)10.2(

aa

acosasina

asinacosa

)9.2(

aa

acosasina

asinacosa

zz

yx

yx

zz

y

x

Page 33: 7. Magnetostatic Fieldiirc.khu.ac.kr/uploads/6/3/4/3/63434825/sadiku_ch07.pdf · 2019-11-23 · 12 2013. 1 학기기말고사: J =(x,0,0)일때중심이원점에있고반지름이a인구의표면을통과하여

32

예제 7.4 길이 L, 반경 a, 권선수 N 인 solenoid에전류 I가흐른다.

다음을유도하라.

(a) 축상의임의의 P 점에서

H =nI

2(cosθ2 − cosθ1)az

where n=N/L

Fig 7.9 Cross section of solenoid.

θ2

θ

P

dz I

L

z

a θ1

Page 34: 7. Magnetostatic Fieldiirc.khu.ac.kr/uploads/6/3/4/3/63434825/sadiku_ch07.pdf · 2019-11-23 · 12 2013. 1 학기기말고사: J =(x,0,0)일때중심이원점에있고반지름이a인구의표면을통과하여

33

z12

12

z

2/322

2

2/322

2

2/322

2

z

2/322

2

z

a)cos(cos2

nIH

)cos(cos2

nI

dsin2

nIH

dsin2

nI

)za(2

dznIa

)za(2

a)Indz(

)za(2

dIadH

L/Nn

3.7from)h(2

IH

2

1

예제

dsina

)za(dz

2

2/322

θ2

θ

P

dz I

L

z

a θ1

Page 35: 7. Magnetostatic Fieldiirc.khu.ac.kr/uploads/6/3/4/3/63434825/sadiku_ch07.pdf · 2019-11-23 · 12 2013. 1 학기기말고사: J =(x,0,0)일때중심이원점에있고반지름이a인구의표면을통과하여

34

3.7from)h(2

IH

2/322

2

z 예제

x

y

z

dHz

dHρ

dL aρ

ρ𝜑

R

P(0,0,h)

I

Page 36: 7. Magnetostatic Fieldiirc.khu.ac.kr/uploads/6/3/4/3/63434825/sadiku_ch07.pdf · 2019-11-23 · 12 2013. 1 학기기말고사: J =(x,0,0)일때중심이원점에있고반지름이a인구의표면을통과하여

35

dsina

)za(

dsina

)za(a

dsincsca

dcscadz

sin

1a

sin

coscossinsina

d

dz

sin

cosaz

z/atan

2

2/322

32/122

3

2

22tan 1 cot

sin cos

cscsec

2

22

secd

tand

sind

cosd

cosd

sind

tantan1

tantan)tan(

sincos)2cos(

sinsincoscos)cos(

cossin2)2sin(

sincoscossin)sin(

θ2

θ

P

dz I

L

z

a θ1

Page 37: 7. Magnetostatic Fieldiirc.khu.ac.kr/uploads/6/3/4/3/63434825/sadiku_ch07.pdf · 2019-11-23 · 12 2013. 1 학기기말고사: J =(x,0,0)일때중심이원점에있고반지름이a인구의표면을통과하여

36

zz

zz

z22

z12

122

2

z

aL

NIanIH

aL

NIanI

a4/La2

InL

a)cos(cos2

nIH

cos)2/L(a

2/Lcos

P

aLforcenterataL

NIH)b(

중심에서가

θ2

θ

P

dz I

L

z

a θ1

Page 38: 7. Magnetostatic Fieldiirc.khu.ac.kr/uploads/6/3/4/3/63434825/sadiku_ch07.pdf · 2019-11-23 · 12 2013. 1 학기기말고사: J =(x,0,0)일때중심이원점에있고반지름이a인구의표면을통과하여

37

7.3 AMPERE’S CIRCUIT LAW – MAXWELL’S EQUATION

)19.7(JH

)18.7(SdJI

)17.7(Sd)H(

LdHI

)16.7()lawcircuits'Ampere(ILdH

Senc

S

Lenc

enc

HI

Ld

Page 39: 7. Magnetostatic Fieldiirc.khu.ac.kr/uploads/6/3/4/3/63434825/sadiku_ch07.pdf · 2019-11-23 · 12 2013. 1 학기기말고사: J =(x,0,0)일때중심이원점에있고반지름이a인구의표면을통과하여

38

7.4 APPLICATION OF AMPERE’S LAW

A. Infinite Line Current

Fig 7.10 Ampere’s law applied to

an infinite filamentary line current.

a2

IH

2

IH

I2H

ILdH)16.7(

a2

IH)14.7(

a)cos(cos4

IH)12.7(

)20.7(a2

IH

enc

12

Page 40: 7. Magnetostatic Fieldiirc.khu.ac.kr/uploads/6/3/4/3/63434825/sadiku_ch07.pdf · 2019-11-23 · 12 2013. 1 학기기말고사: J =(x,0,0)일때중심이원점에있고반지름이a인구의표면을통과하여

39

B. Infinite Sheet of Current

)c21.7(bH2

]b[]H[

]a[]0[

]b[]H[

]a[]0[

LdHLdH

)b21.7(0zaH

0zaHH

)a21.7(bKILdH

o

0

0

1

4

4

3

3

2

2

1

x0

x0

yenc

K

H

H0ax H0ax

-H0ax -H0ax

zx

Page 41: 7. Magnetostatic Fieldiirc.khu.ac.kr/uploads/6/3/4/3/63434825/sadiku_ch07.pdf · 2019-11-23 · 12 2013. 1 학기기말고사: J =(x,0,0)일때중심이원점에있고반지름이a인구의표면을통과하여

40

𝐝𝐇는 -𝐚𝐱 방향

𝐝 𝐋은 -𝐚𝐳 방향

𝐝𝐇는 𝐚𝐱 방향

𝐝 𝐋은 -𝐚𝐳 방향

Page 42: 7. Magnetostatic Fieldiirc.khu.ac.kr/uploads/6/3/4/3/63434825/sadiku_ch07.pdf · 2019-11-23 · 12 2013. 1 학기기말고사: J =(x,0,0)일때중심이원점에있고반지름이a인구의표면을통과하여

41

)23.7(aK2

1H

)22.7(

0zaK2

1

0zaK2

1

H

)c21.7(bH2LdH

)b21.7(0zaH

0zaHH

)a21.7(bKILdH

n

xy

xy

o

x0

x0

yenc

Page 43: 7. Magnetostatic Fieldiirc.khu.ac.kr/uploads/6/3/4/3/63434825/sadiku_ch07.pdf · 2019-11-23 · 12 2013. 1 학기기말고사: J =(x,0,0)일때중심이원점에있고반지름이a인구의표면을통과하여

42

C. Infinitely Long Coaxial Transmission Line

)26.7(ba2

IH

)25.7(a0a2

IH

)24.7(SdJILdH

2

L enc1

Page 44: 7. Magnetostatic Fieldiirc.khu.ac.kr/uploads/6/3/4/3/63434825/sadiku_ch07.pdf · 2019-11-23 · 12 2013. 1 학기기말고사: J =(x,0,0)일때중심이원점에있고반지름이a인구의표면을통과하여

43

)25.7(a2

IH

H2LdH

aISdJ

a0

)24.7(SdJILdH

2

L

2

2

enc

L enc

1

1

)26.7(2

IH

H2LdH

a

aISdJ

ba

1L

2

2

enc

Page 45: 7. Magnetostatic Fieldiirc.khu.ac.kr/uploads/6/3/4/3/63434825/sadiku_ch07.pdf · 2019-11-23 · 12 2013. 1 학기기말고사: J =(x,0,0)일때중심이원점에있고반지름이a인구의표면을통과하여

44

)27.7(bt2t

b1

2

IH

H2LdH

b)tb(

bIISdJ

tbb

2

22

L

22

22

encenc

1

)28.7(0H

tb

Page 46: 7. Magnetostatic Fieldiirc.khu.ac.kr/uploads/6/3/4/3/63434825/sadiku_ch07.pdf · 2019-11-23 · 12 2013. 1 학기기말고사: J =(x,0,0)일때중심이원점에있고반지름이a인구의표면을통과하여

45

)29.7(

tb0

tbbabt2t

b1

2

I

baa2

I

a0aa2

I

H

2

22

2

Fig 7.13 Plot of Hφ against ρ.

1

2πa

1

2πb

ρ0 a b b+t

Page 47: 7. Magnetostatic Fieldiirc.khu.ac.kr/uploads/6/3/4/3/63434825/sadiku_ch07.pdf · 2019-11-23 · 12 2013. 1 학기기말고사: J =(x,0,0)일때중심이원점에있고반지름이a인구의표면을통과하여

46

예제 7.5 z=0, z=4 인 평면에 𝐊 = −𝟏𝟎𝐚𝐱 𝐀/𝐦, 𝐊 = 𝟏𝟎𝐚𝐱 𝐀/𝐦 인 전류가 흐른다.

다음 point에서 𝐇를구하라.(a) (1,1,1) (b) (0,-3,0)

an

z=4

(1,1,1)an

x y

z

z=0

Fig 7.14 Parallel infinite current sheets.

K

m/Aa10HHH

m/Aa5)a()a10(2

1aK

2

1H

m/Aa5a)a10(2

1aK

2

1H

aK2

1H)3.7(

)1,1,1()a(

y40

yzxn4

yzxn0

n

Page 48: 7. Magnetostatic Fieldiirc.khu.ac.kr/uploads/6/3/4/3/63434825/sadiku_ch07.pdf · 2019-11-23 · 12 2013. 1 학기기말고사: J =(x,0,0)일때중심이원점에있고반지름이a인구의표면을통과하여

47

anz=4

(0,-3,10)

an

x y

z

z=0

K

m/Aa0HHH

m/Aa5a)a10(2

1aK

2

1H

m/Aa5a)a10(2

1aK

2

1H

aK2

1H)3.7(

)10,3,0()b(

y40

yzxn4

yzxn0

n

Page 49: 7. Magnetostatic Fieldiirc.khu.ac.kr/uploads/6/3/4/3/63434825/sadiku_ch07.pdf · 2019-11-23 · 12 2013. 1 학기기말고사: J =(x,0,0)일때중심이원점에있고반지름이a인구의표면을통과하여

48

예제 7.6 toroid에서 권선수 N 이고 전류 I 가 흐른다.

toroid 안과 밖에서 𝐇를 구하라.

0H0SdJ

L

NI

)toroid(2

NI

2

NIH

NI2H

I2HLdH)a27.7(

S

00

enc

밖에서는

반지름중심

𝐋

𝐒

𝐈

Page 50: 7. Magnetostatic Fieldiirc.khu.ac.kr/uploads/6/3/4/3/63434825/sadiku_ch07.pdf · 2019-11-23 · 12 2013. 1 학기기말고사: J =(x,0,0)일때중심이원점에있고반지름이a인구의표면을통과하여

49

7.5 MAGNETIC FLUX DENSTY – MAXWELL’S EQUATION

E )(

)Law'Gaussor Eq sMaxwell'4th (the

)34.7(0B

)33.7(0SdB

]Gauss000,10Tesla1

Teslam/Wb[B

)32.7(]Wb[SdB

space) free ofity (Permeabil:

)31.7(m/H104

)30.7(]Tesla[HB

2

S

70

0

Page 51: 7. Magnetostatic Fieldiirc.khu.ac.kr/uploads/6/3/4/3/63434825/sadiku_ch07.pdf · 2019-11-23 · 12 2013. 1 학기기말고사: J =(x,0,0)일때중심이원점에있고반지름이a인구의표면을통과하여

50

N

S

I

MagneticFluxLine

Fig 7.16 magnetic flux line due to a

straight wire with current

coming out of the page

Page 52: 7. Magnetostatic Fieldiirc.khu.ac.kr/uploads/6/3/4/3/63434825/sadiku_ch07.pdf · 2019-11-23 · 12 2013. 1 학기기말고사: J =(x,0,0)일때중심이원점에있고반지름이a인구의표면을통과하여

51

Page 53: 7. Magnetostatic Fieldiirc.khu.ac.kr/uploads/6/3/4/3/63434825/sadiku_ch07.pdf · 2019-11-23 · 12 2013. 1 학기기말고사: J =(x,0,0)일때중심이원점에있고반지름이a인구의표면을통과하여

52

7.6 MAXWELL’S EQUATIONS FOR STATIC EM FIELD

Law sAmpere' SdJLdHJH

field ticelectrosta

of venessConservati 0LdE0E

monopole magnetic

of ceNonexisten 0SdB0B

Law sGauss' dxdydzSdDD

Remark formIntegralformPoint

SL

L

S

vSv

Page 54: 7. Magnetostatic Fieldiirc.khu.ac.kr/uploads/6/3/4/3/63434825/sadiku_ch07.pdf · 2019-11-23 · 12 2013. 1 학기기말고사: J =(x,0,0)일때중심이원점에있고반지름이a인구의표면을통과하여

53

dSaJLdHdSa)H(

JH

EqAmperet

DJ

B

LdEdSa)E(

0E

EqFaradayt

BE

0dSaB

dV)0B(

EqGauss0B

dVdSaD

dV)E(

EqGaussE

nn

n

n

vn

v

v

Page 55: 7. Magnetostatic Fieldiirc.khu.ac.kr/uploads/6/3/4/3/63434825/sadiku_ch07.pdf · 2019-11-23 · 12 2013. 1 학기기말고사: J =(x,0,0)일때중심이원점에있고반지름이a인구의표면을통과하여

54

7.7 MAGNETIC SCALAR AND VECTOR POTENTIALS

)a35.7(VE

0E0)V(

)b35.7(AB

0B0)A(

)36.7(VH

0J if0H0)V(

mm

)39.7(AB

EqAmperet

DJ

B

EqFaradayt

BE

EqGauss0B

EqGaussE v

Page 56: 7. Magnetostatic Fieldiirc.khu.ac.kr/uploads/6/3/4/3/63434825/sadiku_ch07.pdf · 2019-11-23 · 12 2013. 1 학기기말고사: J =(x,0,0)일때중심이원점에있고반지름이a인구의표면을통과하여

55

)36.7(0J if0HVH m

)38.7(0V

0VH

m2

m2

EqAmperet

DJ

B

EqFaradayt

BE

EqGauss0B

EqGaussE v

Page 57: 7. Magnetostatic Fieldiirc.khu.ac.kr/uploads/6/3/4/3/63434825/sadiku_ch07.pdf · 2019-11-23 · 12 2013. 1 학기기말고사: J =(x,0,0)일때중심이원점에있고반지름이a인구의표면을통과하여

56

(7.43)current for volumeR4

dvJA

(7.42)current surfacefor R4

dSKA

(7.41)current linefor R4

LdIA

)40.7(r4

dQV

v0

S0

L0

0

Page 58: 7. Magnetostatic Fieldiirc.khu.ac.kr/uploads/6/3/4/3/63434825/sadiku_ch07.pdf · 2019-11-23 · 12 2013. 1 학기기말고사: J =(x,0,0)일때중심이원점에있고반지름이a인구의표면을통과하여

57

K

a

1

IdL = K ∙ adL

= Ka ∙ dL

= KdS

dL

an

J

Ld

dvJ

LdAJ

LdAJLId

J

na

A

Page 59: 7. Magnetostatic Fieldiirc.khu.ac.kr/uploads/6/3/4/3/63434825/sadiku_ch07.pdf · 2019-11-23 · 12 2013. 1 학기기말고사: J =(x,0,0)일때중심이원점에있고반지름이a인구의표면을통과하여

58

유도

L0

R4

LdIA)41.7(

L0

L0

L0

L0

L 30

L 30

3

RR

LId

4A

ARR

LId

4

RR

LId

4

RR

1LId

4

RR

)RR(LId

4B

R

RLId

4B

R

RLdkIBd

RR

1f

LIdu

ufuf)uf(

)i(장뒷

)ii(장뒷

R

R

R R

R

R

vd 𝐁

𝐑~𝐚𝐫

𝐝 𝐋 I

P

Page 60: 7. Magnetostatic Fieldiirc.khu.ac.kr/uploads/6/3/4/3/63434825/sadiku_ch07.pdf · 2019-11-23 · 12 2013. 1 학기기말고사: J =(x,0,0)일때중심이원점에있고반지름이a인구의표면을통과하여

59

3

2/3222

zyx

z2/32222/1222

z

y2/32222/1222

y

x2/3222

2/3222x

2/1222x

2/1222zyx

R

R

R

1

)zyx(

azayax

R

1

)az()zyx()zyx(z

a

)ay()zyx()zyx(y

a

)ax()zyx(

)x2()zyx(2

1a)zyx(

xa

)zyx(z

ay

ax

aR

1

)dzzd,dyyd,dxxd

)zz,yy,xx()z,y,x(

RRR

3

L0

L 30

RR

RR

RR

1

RR

1LId

4

RR

)RR(LId

4B

(i)

Page 61: 7. Magnetostatic Fieldiirc.khu.ac.kr/uploads/6/3/4/3/63434825/sadiku_ch07.pdf · 2019-11-23 · 12 2013. 1 학기기말고사: J =(x,0,0)일때중심이원점에있고반지름이a인구의표면을통과하여

60

RR

LId

RR

1LId

RR

LId

4

RR

1LId

4B

L0

L0

RR

1)LId(

RR

LId

RR

1)LId(

)LId(RR

1

)LId(RR

1

)LId(RR

1LId

RR

1

RR

1f

LIdu

ufuf)uf(

(ii)

Page 62: 7. Magnetostatic Fieldiirc.khu.ac.kr/uploads/6/3/4/3/63434825/sadiku_ch07.pdf · 2019-11-23 · 12 2013. 1 학기기말고사: J =(x,0,0)일때중심이원점에있고반지름이a인구의표면을통과하여

61

)51.7(LdA

SdA

SdB

L

S

S

Page 63: 7. Magnetostatic Fieldiirc.khu.ac.kr/uploads/6/3/4/3/63434825/sadiku_ch07.pdf · 2019-11-23 · 12 2013. 1 학기기말고사: J =(x,0,0)일때중심이원점에있고반지름이a인구의표면을통과하여

62

Wb75.3

dzd2

1

SdB)32.7(

a2

AB

1Method

5

0z

2

1

S

뒷장

뒷장

a2

AAA

z

aaa

1A

z

z

예제 7.7 A = −(ρ2/4)az 일 때 φ=π/2, 1≤ρ≤2 m, 0≤z≤5 m 인면을 통과하는 자속 ψ를 구하라.

Fig 7.20 For example 7.7

3

2 4

11

2

3

4

5

ρ

z

2

L

B A

3

S

1

Page 64: 7. Magnetostatic Fieldiirc.khu.ac.kr/uploads/6/3/4/3/63434825/sadiku_ch07.pdf · 2019-11-23 · 12 2013. 1 학기기말고사: J =(x,0,0)일때중심이원점에있고반지름이a인구의표면을통과하여

63

a2

a4

1

4/00

00

aaa

1

AAA

z

aaa

1A

2

2

z

z

z

Page 65: 7. Magnetostatic Fieldiirc.khu.ac.kr/uploads/6/3/4/3/63434825/sadiku_ch07.pdf · 2019-11-23 · 12 2013. 1 학기기말고사: J =(x,0,0)일때중심이원점에있고반지름이a인구의표면을통과하여

64Wb75.3

dz4

0

dz4

0

LdA

SdA

SdB

2Method

0

5

2

2

5

0

1

2

4321

L

S

S

예제 7.7 A = −(ρ2/4)az 일 때 φ=π/2, 1≤ρ≤2 m, 0≤z≤5 m 인면을 통과하는 자속 ψ를 구하라.

3

2 4

11

2

3

4

5

ρ

z

2

L

A

Fig 7.20 For example 7.7

3

1

Page 66: 7. Magnetostatic Fieldiirc.khu.ac.kr/uploads/6/3/4/3/63434825/sadiku_ch07.pdf · 2019-11-23 · 12 2013. 1 학기기말고사: J =(x,0,0)일때중심이원점에있고반지름이a인구의표면을통과하여

65

0zaK2

1

0zaK2

1

H)22.7(

xy

xy

예제 7.8 z=0 인면에 K = Kyay 의 면전류가 흐를 때 다음을 유도하라.

Page 67: 7. Magnetostatic Fieldiirc.khu.ac.kr/uploads/6/3/4/3/63434825/sadiku_ch07.pdf · 2019-11-23 · 12 2013. 1 학기기말고사: J =(x,0,0)일때중심이원점에있고반지름이a인구의표면을통과하여

66

x0

2

0 2/322

y0

x2/3222

y0

2/3222

xy0

xy

222

yy0

0

S0

a)z(4

)dd(zK

a)zyx(4

)ydxd(zKB

)zyx(4

a)ydxd(zK

)adA(z

AdAdBd

zyx4

)ydxd(aK

R4

dSKAd

R4

dSKA)42.7(

xy

zyxy

y

zyx

a)dA(z

a)dA(x

a)dA(z

0dA0

zyx

aaa

Ad

Page 68: 7. Magnetostatic Fieldiirc.khu.ac.kr/uploads/6/3/4/3/63434825/sadiku_ch07.pdf · 2019-11-23 · 12 2013. 1 학기기말고사: J =(x,0,0)일때중심이원점에있고반지름이a인구의표면을통과하여

67

x0

2

0 2/322

y0

x2/3222

y0

a)z(4

)dd(zK

a)zyx(4

)ydxd(zKB

Page 69: 7. Magnetostatic Fieldiirc.khu.ac.kr/uploads/6/3/4/3/63434825/sadiku_ch07.pdf · 2019-11-23 · 12 2013. 1 학기기말고사: J =(x,0,0)일때중심이원점에있고반지름이a인구의표면을통과하여

68

0zfor2

aK

z

1

2

azK

0zfor2

aK

z

1

2

azK

z

10

2

azK

)zt(24

azK

dt)zt(4

azK

dtd2

ta

)zt(8

zdtK2

a)z(4

dzK2

a)z(4

)dd(zKB

xy0xy0

xy0xy0

2

xy0

02/12xy0

0t2/32xy0

2

x0t 2/32

y0

x0 2/322

y0

x0

2

0 2/322

y0

Page 70: 7. Magnetostatic Fieldiirc.khu.ac.kr/uploads/6/3/4/3/63434825/sadiku_ch07.pdf · 2019-11-23 · 12 2013. 1 학기기말고사: J =(x,0,0)일때중심이원점에있고반지름이a인구의표면을통과하여

69

7.8 Biot-Savart 법칙과 Ampere 법칙유도

전선에 전류 I가 흐르면 Point P에 전선에 수직인 방향으로 자장이 발생한다.

30

3

x

xLId

4

x

xLdkIBd

Biot와 Savart가 정교하고 철저한 실험에 의해 전류가 흐르는 전선에 의해point P에서 발생하는 자장은 전선과point P의 거리의 제곱에 역 비례하고전선과 𝐱 에 수직인 방향으로 발생한다는 것을 알았다.

𝐁

𝐱

𝐝 𝐋 I

P

Page 71: 7. Magnetostatic Fieldiirc.khu.ac.kr/uploads/6/3/4/3/63434825/sadiku_ch07.pdf · 2019-11-23 · 12 2013. 1 학기기말고사: J =(x,0,0)일때중심이원점에있고반지름이a인구의표면을통과하여

70

xdxx

)x(J

4

)x(JA

xx

1f

AfAf)Af(

xdxx

)x(J

4

xd)x(Jxx

1

4

xdxx

1)x(J

4

xd)x(J

LAd)x(JLIdxd

xx

)xx()x(J

4)x(B

x

xLId

4Bd

30

30

30

30

3

3

30

30

장뒷

x

x

x

x

Page 72: 7. Magnetostatic Fieldiirc.khu.ac.kr/uploads/6/3/4/3/63434825/sadiku_ch07.pdf · 2019-11-23 · 12 2013. 1 학기기말고사: J =(x,0,0)일때중심이원점에있고반지름이a인구의표면을통과하여

71

3

2/3222

zyx

z2/32222/1222

z

y2/32222/1222

y

x2/3222

2/3222x

2/1222x

2/1222zyx

R

R

R

1

)zyx(

azayax

R

1

)az()zyx()zyx(z

a

)ay()zyx()zyx(y

a

)ax()zyx(

)x2()zyx(2

1a)zyx(

xa

)zyx(z

ay

ax

aR

1

)dzzd,dyyd,dxxd

)zz,yy,xx()z,y,x(

RRR

3

L0

L 30

RR

RR

RR

1

RR

1LId

4

RR

)RR(LId

4B

Page 73: 7. Magnetostatic Fieldiirc.khu.ac.kr/uploads/6/3/4/3/63434825/sadiku_ch07.pdf · 2019-11-23 · 12 2013. 1 학기기말고사: J =(x,0,0)일때중심이원점에있고반지름이a인구의표면을통과하여

72

RR

LId

RR

1LId

RR

LId

4

RR

1LId

4B

L0

L0

RR

1)LId(

RR

LId

RR

1)LId(

)LId(RR

1

)LId(RR

1

)LId(RR

1LId

RR

1

RR

1f

LIdu

ufuf)uf(

Page 74: 7. Magnetostatic Fieldiirc.khu.ac.kr/uploads/6/3/4/3/63434825/sadiku_ch07.pdf · 2019-11-23 · 12 2013. 1 학기기말고사: J =(x,0,0)일때중심이원점에있고반지름이a인구의표면을통과하여

73xd)xx()x(J

)xx(4xx

1xd)]xx(4[)x(J

4

xdxx

1)x(J

4

xdxx

)x(J

4Sd

xx

)x(J

4

xdxx

)x(J

4xd

xx

)x(J

4

xdxx

)x(J

4xd

xx

)x(J

4

A)A()A(xdxx

)x(J])([

4

xdxx

)x(J

4)x(B

xdxx

)x(J

4)x(Axd

xx

)x(J

4)x(B

30

230

320

3200

32030

32030

2320

30

3030

Page 75: 7. Magnetostatic Fieldiirc.khu.ac.kr/uploads/6/3/4/3/63434825/sadiku_ch07.pdf · 2019-11-23 · 12 2013. 1 학기기말고사: J =(x,0,0)일때중심이원점에있고반지름이a인구의표면을통과하여

74

tJ

0Jt

E

Jt

EB

Jt

EB

?0J

JB

)(

)x(f)xx()x(f)x(J)x(B

xd)xx()x(J)x(B

)xx(4xx

1xd)]xx(4[)x(J

4)x(B

v

0

00

00

0

000

30

230

Page 76: 7. Magnetostatic Fieldiirc.khu.ac.kr/uploads/6/3/4/3/63434825/sadiku_ch07.pdf · 2019-11-23 · 12 2013. 1 학기기말고사: J =(x,0,0)일때중심이원점에있고반지름이a인구의표면을통과하여

75

0r

1

0r)1(

r

1

rr

rr

1

r

1

r

1

xx

1

)xx(4xx

1:

2

2

2

2

22

2

경우인

유도

Page 77: 7. Magnetostatic Fieldiirc.khu.ac.kr/uploads/6/3/4/3/63434825/sadiku_ch07.pdf · 2019-11-23 · 12 2013. 1 학기기말고사: J =(x,0,0)일때중심이원점에있고반지름이a인구의표면을통과하여

76

0 2/522

22

0a

230

2

2/522

2

0a

2

2

23

2/522

2

0a

3

22

2

0a

3

22

2

0a

32

)ar(

drra12

drr4xd)drr4()ar(

1a3

rr

rr

1xd

)ar(

1a3

xdar

1

xdar

1

xdr

1

0r)2(

lim

lim

lim

lim

lim

경우인

Page 78: 7. Magnetostatic Fieldiirc.khu.ac.kr/uploads/6/3/4/3/63434825/sadiku_ch07.pdf · 2019-11-23 · 12 2013. 1 학기기말고사: J =(x,0,0)일때중심이원점에있고반지름이a인구의표면을통과하여

77

4

dcosdt

sintdtt12

dcossin12

sec

dtan12

dsecadr

tanar

)1(tan

dsectan12

)ar(

drra12

xdr

1

1

02

2/

02

2/

0 3

2

2

2/

0 2/52

22

0 2/522

22

0a

32

lim

tan 1 cot

sin cos

cscsec

2

22

secd

tand

sind

cosd

cosd

sind

tantan1

tantan)tan(

sincos)2cos(

sinsincoscos)cos(

cossin2)2sin(

sincoscossin)sin(

Page 79: 7. Magnetostatic Fieldiirc.khu.ac.kr/uploads/6/3/4/3/63434825/sadiku_ch07.pdf · 2019-11-23 · 12 2013. 1 학기기말고사: J =(x,0,0)일때중심이원점에있고반지름이a인구의표면을통과하여

78

δ(x-x0)

x0 x0+Δx

x

1/Δx

Δx

)x(fdx)xx()x(f 00

0r

1

0r)1(

2

경우인

4xdr

1

0r)2(

32

경우인

)xx(4xx

12

Page 80: 7. Magnetostatic Fieldiirc.khu.ac.kr/uploads/6/3/4/3/63434825/sadiku_ch07.pdf · 2019-11-23 · 12 2013. 1 학기기말고사: J =(x,0,0)일때중심이원점에있고반지름이a인구의표면을통과하여

79

)x(fdx)xx()x(f

)x(f

xx

)x(f

dxx

1)x(flim

dx0)x(fdxx

1)x(fdx0)x(flim

dx)xx()x(fdx)xx()x(fdx)xx()x(f

dx)xx()x(f

)x(fdx)xx()x(f

00

0

0

xx

x0x

xx 0xx

x

x

0x

xx 0xx

x 0x

0

0

00

0

0

0

0

0

0

0

0

0

0

유도

δ(x-x0)

x0 x0+Δx

x

1/Δx

Δx

Page 81: 7. Magnetostatic Fieldiirc.khu.ac.kr/uploads/6/3/4/3/63434825/sadiku_ch07.pdf · 2019-11-23 · 12 2013. 1 학기기말고사: J =(x,0,0)일때중심이원점에있고반지름이a인구의표면을통과하여

80

0t/where

)60.7(JA

Jt

EA

1

A

A)A(

AB

AB)39.7(0B

Jt

EB

02

02

0

2

2

00

)59.7(0)x(A

xx

Sd)x(J

4

xdxx

)x(J

4

xdxx

)x(J)(

4

xdxx

)x(J

4

xdxx

)x(J

4)x(A

xdxx

)x(J

4)x(A

0

30

30

30

30

30

(7.59) & (7.60) 유도