Peoples Physics Concepts

15.5. Capacitors Circuits http://www.ck12.org

Solution

(a): In solving this problem, we’ll call the 20μF capacitorC 1 , the 60μF capacitorC 2 , the 40μF capacitorC 3 , and

the 100μF capacitorC 4.

Our first step will be to find the equivalent capacitance ofC 2 andC 3.

1

C 2 , 3

=

1

C 2

+

1

C 3

1

C 2 , 3

=

1

60 μF

+

1

40 μF

1

C 2 , 3

=

5

120 μF

C 2 , 3 =24 F

Next, we’ll combine the capacitance ofC 2 , 3 andC 4.

C 2 , 3 , 4 =C 2 , 3 +C 4

C 2 , 3 , 4 = 24 μF+ 100 μF

C 2 , 3 , 4 = 124 μF

Finally, we can combineC 2 , 3 , 4 withC 1 to find the total capacitance.