Created by Jamari, S.Pd.

CAPASITORCAPASITOR

Source : Haliday-Resnick-Walker

Adaptif

CAPASITOR

A capasitor consist of two parallel conducting plate, each of area A, that separated by dielectric material/isolator/ vaccum

A capasitor consist of two parallel conducting plate, each of area A, that separated by dielectric material/isolator/ vaccum

Between two plate are related with different electric potential V. Each plate carries equal amount of charge. One plate carries positive charge and the other caries negative charge.

Between two plate are related with different electric potential V. Each plate carries equal amount of charge. One plate carries positive charge and the other caries negative charge.

Source: Haliday-Resnick-Walker

Dielectric materials

Area =A

Adaptif

CAPASITOR

Characteristic of capasitor Can save electric energy

without chemistry reaction Can’t be passed by DC

electric current, but can be passed easily by AC electric current

If it is related with different electric potential, each plate carries equal amount of charge. One plate carries positive charge and the other caries negative charge.

Hal.: 3 Characteristic of capasitor

Symbol of capasitor

+V

+Q -Q

Adaptif

CAPASITANCE of CAPASITOR

Capasitance of capasitor (C) shows the amount of charge in each plate, if both of them have different electric potential 1 volt

Hal.: 4 Capasitance of Capasitor

+V

+Q -Q

V

V

QC Q = the amount of charge in each plate

V = different electric potential between two plates (Volt)C = Capasitance of capasitor (Farad = F )

AdaptifHal.: 5 Capasitance of Capasitor

vaccum

Area =A

V

QC

d

xAεC o

C = capasitance of capasitor (Farad= F)

d = distance (meter)

A = surface area (meter 2 )

o = permitivitas udara atau ruang hampa

( 8.854 187 82 · 10-12 C/vm )

dAεQQ

Exd

QC

o

x

CAPASITANCE of CAPASITOR

AdaptifHal.: 6 Capasitance of Capasitor

Dielectrics materials

Area =A

d

εxAC

= permitivitas bahan dielektrik (C/vm )

K.εε o

K = dielectric constanta (vaccum, K = 1 )

CAPASITANCE of CAPASITOR

Adaptif

CAPASITOR

Series circuit

Hal.: 7 Series circuit

+V

+Q1-Q1 +Q2

-Q2

1. Capasitance of capasitor (Cg ), Capasitance of 1st capasitor (C1), Capasitance of 2nd capasitor (C2) is:

2. The charge that is kept in circuit= the charge in each capasitor. Q = Q1 + Q2 dan Q1 = Q2

3. Electric potential(V), potential at 1st capasitor (V1 ) and 2nd capasitor (V2 ) is:V = V1 + V2

1. Capasitance of capasitor (Cg ), Capasitance of 1st capasitor (C1), Capasitance of 2nd capasitor (C2) is:

2. The charge that is kept in circuit= the charge in each capasitor. Q = Q1 + Q2 dan Q1 = Q2

3. Electric potential(V), potential at 1st capasitor (V1 ) and 2nd capasitor (V2 ) is:V = V1 + V2

21g C

1

C

1

C

1

Adaptif

Circuit of Capasitor

Series Circuit

Hal.: 8 Series Circuit

+V = 6 volt

+Q -Q +Q -Q

C1 = 2 F C2 = 3 F

Example:Example:

1. Kapasitance of capasitor :

Cg = 6/5 = 1,2 F

2. The charge in the circuit = 1,2 F x 6V = 7,2 C 1st capasitor = 7,2 C 2nd capasitor = 7,2 C

3. Electric potential: 1st capasitor = 3,6 V 2nd capasitor = 2,4 V

1. Kapasitance of capasitor :

Cg = 6/5 = 1,2 F

2. The charge in the circuit = 1,2 F x 6V = 7,2 C 1st capasitor = 7,2 C 2nd capasitor = 7,2 C

3. Electric potential: 1st capasitor = 3,6 V 2nd capasitor = 2,4 V

6

5

6

23

3

1

2

1

C

1

g

Adaptif

Circuit of Capasitor

Paralel Circuit

Hal.: 9 Paralel Circuit

+V

+Q1-Q1

+Q2-Q2

1) Potential at 1st capasitor (V1), 2nd capasitor (V2) and at the source potential (V) is V1 = V2 = V

2) The charge that is kept in the circuit is Q = Q1 + Q2

3) Capasitance of union of capasitor is: Cg = C1 + C2

Adaptif

Circuit of Capasitor

Paralel Circuit

Hal.: 10 Paralel Circuit

1. Each capasitor has same potential, then we get V1 = V2 = 6 volt

2. Capasitance of capasitor is Cg = C1 + C2 = 2F + 3F = 5F

3. The charges that are kept in the circuit are:

Q = Cg xV = 5F x 6V = 30CQ1 = C1 x V = 2Fx6V = 12C

Q2 = C2 x V = 3Fx6V = 18C

Example: Example:

+

+Q1-Q1

+Q2-Q2

C1 = 2 F

C2 = 3 F

V = 6 volt

Adaptif

Electric energy that is kept at capasitor The Graphics of relation the voltage (V) with the

charges in capasitor (Q)

Hal.: 11 Electric Energy in Capasitor

V(volt)

Q(Coulomb)Electric energy in capasitor that has charge Q = surface areaunder curva graphics Q-V (the hatching ).

Q

V

QV2

1W

Adaptif

Electric energy that is kept at capasitor

Hal.: 12 Electric Energy in Capasitor

(CV)V2

1W

+V

A capasitor has capasitance C is connected with voltage V.

Cbecause Q = C.V, so

2CV2

1W

W = electric energy in capasitor (Joule)

Q = Charge in capasitor (Coulomb)

C = Capasitance of capasitor (farad)

V = Voltage between parallelplate capasitor (Volt)