Worked Annotated Sample Problems - create

advertisement

Series Circuit Samples

1) Connect each set of resistors in Figure 5-67 in series between points A and B.

R1

A

A B A

R2

B

R2

B

R1 R2 R3 R1

R3

R4 R5

R3

Figure 5-67(a) Figure 5-67(b) Figure 5-67(c)

7) The current from the source in Figure 5-70 is 5mA. How much current does each milliammeter in the circuit indicate?

The current is the same everywhere in a series circuit, therefore each meter will read 5mA

12) Calculate RT for each circuit of Figure 5-71.

1kohm

Es 5.6kohm

R

T

= Ω +

5.6

k

Ω +

2.2

k

Ω ⇒

8.8

k

2.2kohm

Figure 5-71(a)

4.7ohm

10ohm

Es

R

=

4.7

10 12 1

T

27.7

12ohm

1ohm

Figure 5-71(b)

1Mohm 560kohm

5.6Mohm

Es

R 1 M

T

= Ω +

560 k

Ω +

5.6

M

Ω +

680 k

Ω +

10 M

Ω ⇒

17.84

M

680kohm

10Mohm

Figure 5-71(c)

13) What is the total resistance of twelve 5.6kΩ resistor is series?

R

T

=

12(5.6

k ) 67.2

k

15) If the total resistance if Figure 5-72 is 17.4kΩ, what is the value of R

5

?

R

T

=

R

1

+

R

2

+

R

3

+

R

4

+

R

5

R

T

R

1

R

2

R

3

R

4

=

R

5

17.4

k

Ω −

5.6

k 1 k 2.2

k

Ω −

4.7

k

Ω =

R

5

R

5

=

3.9

k

18) What is the total resistance from A to B for each switch position in Figure 5-73.

Position 1 - R

T

=

R

1

+

R

3

+

R

5

2.01

k

Position 2 - R

T

=

R

1

+

R

2

+

R

3

+

R

4

+

R

5

3.67

k

Series Circuit Samples

19) What is the current in each of the following circuits?

R1

2.2kohm

R

T

=

R

1

+

R

2

+

R

3

8.8

k

I

625

µ

A

Es

R2

5.6kohm

=

Es

=

R

T

16 V

8.8

k

5.5V

R3

1kohm

Figure 5-74 (a)

Es

16V

R1

1Mohm

R2

2.2Mohm

R

T

=

R

1

+

R

2

+

R

3

3.76

M

I

=

Es

R

T

16 V

3.76

M

4.26

µ

A

R3

560kohm

I A

(a)

Figure 5-74 (b)

20) Determine the voltage drop across each resistor in Figure 5-74:

=

625

µ

VR

1

=

IR

1

VR

2

=

IR

2

(625

µ

A )(2.2

k

Ω ⇒

1.38

V

(625

µ

A )(5.6

k

Ω ⇒

3.5

V

(625

µ

A )(1.0

k

Ω ⇒

0.625

V

625 mV VR

3

=

IR

3

(b) I

=

4.26

µ

A

VR

1

=

IR

1

(4.26

µ

A )(1 M

Ω ⇒

4.26

V

VR

2

=

IR

2

(4.26

µ

A )(2.2

M

Ω ⇒

9.36

V

VR

3

=

IR

3

(4.26

µ

A )(560 k

Ω ⇒

2.38

V

29) Determine the total source in each circuit of Figure 5-79

-

5V

+

10V

+

-

+

8V

-

Figure 5-79(a)

R

E

T

=

10 V

+

8 V

+

5 V

23 V 23V

-

+ R

+

50V

-

25V

+

35V

+

-

10V

+

-

E

T

=

10 V

+

50 V

25 V

35 V

R

R

Figure 5-79(b)

8V

-

+ R

0V

+

R

E

T

=

8 V

8 V

0 V

8V

+ -

-

Figure 5-79(c)

Es 5.5

V

+

8.2

V

+

12.3

V 26 V

30) The following voltage drops are measured across three resistors in series: 5.5V, 8.2V, and

12.3V. What is the value of the source voltage to which these resistors are connected?

= ⇒

31) Five resistors are in series with a 20V source. The voltage drops across four of the resistors are 1.5V, 5.5V, 3V, and 6V. How much voltage is dropped across the fifth resistor?

Es

=

V

R 1

+

V

R 2

+

V

R 3

+

V

R 4

+

V

R 5

Es V

R 1

V

R 2

V

R 3

V

R 4

=

V

R 5

20 V

1.5

V

5.5

V

3 V

6 V

=

V

R 5

4 V

=

V

R 5

32) Determine the unspecified voltage drop(s) in each circuit of Figure 5-80. Show how to connect a voltmeter to measure each unknown voltage drop.

2V VR2 3.2V

15V

1V

15 V

0.5

V

1.5

V

1 V

3.2

V

V

R 2

2 V

=

0

V

R 2

=

6.8

V

0.5V

1.5V

Figure 5-80(a)

Es

R

8V

R

2R

R

=

8 V

2 R

=

16 V

3 R

=

24 V

4 R

=

32 V

R

+ +

2 R

+

3 R

+

4 R

=

Es

4R 3R 8 V

+

8 V

+

16 V

+

24 V

+

32 V

=

88 V

Figure 5-80(b)

33) In the circuit of Figure 5-81, determine the resistance of R

4

Es

56ohm

11.2V

27ohm 5.4V

4.7ohm

0.94V

R4

4.4V

Figure 5-81

I

=

V

R

R 1

1

11.2

56

V

0.2

A

200 mA

R 4

=

VR 4

I

4.4

V

200 mA

22

Series Circuit Samples

41) What is the voltage across each resistor in Figure 5-86? R is the lowest-value resistor, and all others are multiples of that value as indicated.

R

2R

R

T

=

R

1

+

R

2

+

R

3

+

R

4

+

R

5

RT

= +

2 R

+

3 R

+

4 R

+

5 R

15 R

Voltage Division Rule

Es

90V

5R

3R

4R

V

R

V

2 R

=

R

×

Es

V

R

=

R

T

= ×

V

12 V

V

3 R

= ×

V

18 V

V

4 R

= ×

V

24 V

V

5 R

= ×

V

30 V

R

15 R

×

90 V

6 V

Figure 5-86

49) Find RT in Figure 5-89.

R1 5.6Mohm

I

R

1

=

V

R 1

R

1

12

5.6

V

M

=

5.6

M

Ω given

2.14

µ

A

12V

R2

4.8V

R3

Es R 2

=

V

I

R 2

R 3

=

P

I

R

2

3

4.8

V

2.14

µ

A

21.5

µ

W

(2.14

µ

A )

2

2.24

M

4.69

M

P=21.5uW

Figure 5-89

RT

=

R 1

+

R 2

+

R 3

5.6

M

Ω +

2.24

M

Ω +

4.69

M

51) Determine the voltage at each point with respect to ground in Figure 5-90.

Ω ⇒

12.53

M

Es

100V

A

R1

5.6kohm

R4

1kohm

Figure 5-89

D

B

R2

5.6kohm

C

R3

1kohm

V

V

V

A

B

C

V

D

=

100 V

=

( R

2

+

R

3

+

R

4

)

×

E

S

7.6

k

13.2

k

×

100 V

55.53

V

=

( 3

+

R

T

R 4)

×

E

S

2 k

13.2

k

×

100 V

R

T

=

R

4

×

E

S

R

T

1 k

13.2

k

×

100

7.58

V

15.15

V

Download