Electrical Engineering first year lecuture notes.

1. EEB501: Introduction to Electrical and Electronic
Engineering
Topic: Series and Parallel Circuits
1

2. Resistors Connected
in Series
 The equivalent resistance of any number of resistors connected
in series is the sum of the individual resistances.
 Current remains same while voltage divides
2

3. Resistors Connected
in Parallel
 The equivalent resistance of any number of resistors connected
in parallel is given by:
 Voltage remains same while current divides
3

4. Example
4

5. Example
5

6. Example
6

7. Exercise
7

8. Wye and Delta
Transformations
 Situations often arise in circuit analysis when the resistors are
neither in parallel nor in series.
8

9. Wye Network
9

10. Delta Network
10

11. Delta to Wye Conversion
11

12. Wye to Delta Conversion
12

13. Wye and Delta Conversion
13

14. Example
14

15. Example
15

16. Example
16

17. Exercise - Tutorial
17

18. Series Circuits
 The current remains the
same.
 The sum of the voltages is
same as the applied
voltage.
 The total resistance is the
sum of all the individual
resistance’s.
3
2
1 R
R
R I
I
I
I 


3
2
1 V
V
V
V 


3
2
1 R
R
R
RTotal 


18

19. Series Circuits
19

20. Potential Divider
20

21. Potential Divider
21

22. Potential Divider
22

23. Parallel Networks
 The sum of the currents is
equal to the total circuit
current.
 The voltage across the
resistors is the same as the
applied voltage.
 The total resistance is:
3
2
1 I
I
I
I 


3
2
1 R
R
R V
V
V
V 


3
2
1
1
1
1
1
R
R
R
RTotal



23

24. Parallel Networks
24

25. Parallel Networks
25

26. Parallel Networks
26

27. Parallel Networks
27

28. Current Division
I
R
R
R
I
2
1
2
1

 I
R
R
R
I
2
1
1
2


28

29. Series and Parallel Networks
29

30. Series and Parallel Networks
30

31. Series and Parallel Networks
For the circuit shown below, find the current flowing through and
the voltages across each of the resistors.
Do all questions from Exercise 20 (Page 49 of Text Book).
Students can also attempt Exercises 21 and 22 (optional).
31

32. Capacitors
 Ability to store a quantity of static electricity.
 The charge Q stored in a capacitor is given by Q = I t
 The unit of capacitance is the farad F
32

33. Example
33

34. Example
34

35. Example
35

36. Capacitors Connected
in Parallel
 For n parallel connected capacitors
36

37. Capacitors Connected
in Series
 For n series connected capacitors
37

38. Example
38

39. Example
39

40. Example
40

41. Example
41

42. Example
42

43. Example
43

44. Example
44

45. Thank You