1. Basics of Electronic Circuitsby
Prof. Dr. Nashaat El-Khameesy

2. Course Contents II. Electronics Chap. 2: Resistive Circuits
I. Electric Circuits
Chap. 1: Introduction
Chap. 2: Resistive Circuits
Chap. 3: Inductance and Capacitance
Chap. 4: Transients
Chap. 5: Steady-State Sinusoidal Analysis
Chap. 6: Frequency Response
II. Electronics
Chap.10: Diodes
Chap.11: Amplifiers
Chap.12: Field Effect Transistors
Chap.14: Operational Amplifiers

3. Chapter 1 Introduction
Define current, voltage, and power, including their units.
Calculate power and energy, as well as determine whether energy is supplied or absorbed by a circuit element.
State and apply basic circuit laws.
Solve for currents, voltages, and powers in simple circuits.

4. Chapter 1 Introduction
1.1 The History of Electricity

5. Chapter 1 Introduction
1.1 The History of Electricity

6. Chapter 1 Introduction
1.1 The History of Electricity

7. Chapter 1 Introduction 1.2 Circuits, Currents, and Voltages
An electric circuit consists of various types of elements connected by connectors.
(Note: “open” or “short” circuit)
(a) Open circuit. (b) Short circuit.
1.5 Kirchhoff’s Voltage Law

8. Chapter 1 Introduction 1.2 Circuits, Currents, and Voltages
Electrical current is the time rate of flow of electrical charge through a conductor or circuit element. The units are amperes (A), which are equivalent to coulombs per second (C/s).
We define the direction of positive charge flow as
positive current direction.
1.5 Kirchhoff’s Voltage Law

9. Chapter 1 Introduction 1.2.2 Currents
Actual direction and reference direction
of current flow.
e.g.,
Direct current (dc) and alternating current (ac)

10. Chapter 1 Introduction 1.2.2 Currents Notation for currents:
1.2.3 Voltages
Voltage is the energy transferred per unit of charge that flows through the element:
V (volt) = J (joule)/C (coulomb)
Notice that voltage is measured across the ends of a circuit element,
whereas current is a measure of charge flow through the element.

11. Chapter 1 Introduction
1.2.4 Actual and Reference Polarities of Voltage
Voltages are assigned polarities that indicate the direction of energy flow. ＋ －

12. Chapter 1 Introduction 1.2.5 Voltmeters and Ammeters
(a) A direct-reading (analog) meter.
(b) A digital meter.
(a) An ideal ammeter measures the current flow through its terminals and has zero voltage.
(b) An ideal voltmeter measures the voltage across its terminals and has zero terminal current.

13. Chapter 1 Introduction
1.2.5 Voltmeters and Ammeters
Ideal voltmeters (ammeters) act like open (short) circuits.
(a) An example circuit, (b) plus an open circuit and a short circuit. (c) The open circuit is replaced by a voltmeter, and the short circuit is replaced by an ammeter. All resistances are in ohms.

14. Chapter 1 Introduction
1.2.5 Voltmeters and Ammeters
(a) The correspondence between the color-coded probes of the voltmeter and the reference direction of the measured voltage. In (b) the + sign of vais on the left, while in (c) the + sign of vb is on the right. The colored probe is shown here in blue. In the laboratory this probe will be red. We will refer to the colored probe as the “red probe.”

15. Chapter 1 Introduction
1.2.5 Voltmeters and Ammeters
(a) The correspondence between the color-coded probes of the ammeter and the reference direction of the measured current. In (b) the current ia is directed to the right, while in (c) the current ib is directed to the left. The colored probe is shown here in blue. In the laboratory this probe will be red. We will refer to the colored probe as the “red probe.”

16. Chapter 1 Introduction
1.2.6 Switches

17. Chapter 1 Introduction
1.3 Power and Energy

18. Chapter 1 Introduction 1.3 Power and Energy
Passive reference configuration:
Current reference enters the positive
polarity of the voltage.
In this case, p=vi .
A positive p means energy is being
absorbed by the element; a negative
p means energy is being supplied by
the element.
Note: a positive p for a battery means: charging the battery.

19. 1.3 Power and Energy
Example 1.2

20. Chapter 1 Introduction 1.4 Kirchhoff’s Current Law
Node: a joint of two or more circuit elements
Kirchhoff’s Current Law (KCL):
The net current entering (leaving) a node is zero, or

21. Chapter 1 Introduction
1.4 Kirchhoff’s Current Law
Exercise 1.7

22. Chapter 1 Introduction 1.5 Kirchhoff’s Voltage Law
Loop: a closed electrical path
Kirchhoff’s Voltage Law (KVL):
The algebraic sum of the voltage
equals zero for any loop in an
electrical circuit, or

23. Chapter 1 Introduction 1.5 Kirchhoff’s Voltage Law
Both Kirchhoff’s voltage and current laws are the result of conservation of energy (i.e., power supplied = power absorbed).
KVL KCL

24. Chapter 1 Introduction 1.5 Kirchhoff’s Voltage Law
Two or more circuit elements are in parallel if both ends of one element are connected directly to corresponding ends of others.
In the following figure, D,E,F are in parallel, but not B,D.
The voltage across parallel elements are equal in magnitude and have the same polarity.

25. Chapter 1 Introduction
1.5 Kirchhoff’s Voltage Law

26. Chapter 1 Introduction 1.6 Basic Circuit Elements 1.6.1 Conductors
* Zero voltage drop in (ideal) conductors
* “short circuit”: two points are connected by conductor
All points connected by conductors can be considered as a single point.
* “open circuit”: no connector between two pints in a circuit.

27. Chapter 1 Introduction 1.6.1 Conductors
A sudden increase of the current in a circuit may cause elements (e.g., source) to burnout, sometimes even initiate a fire!
We can use fuses to prevent currents from becoming too large.

28. Chapter 1 Introduction f=1 1.6.2 Voltage Sources
* Independent Voltage Sources maintain a specific voltage across its terminals, independent of other elements in the circuit.
f=1

29. Chapter 1 Introduction 1.6.2 Voltage Sources
* Dependent (or Controlled) Voltage Sources
voltage-controlled voltage source, current-controlled voltage source

30. Chapter 1 Introduction f=50 1.6.3 Current Sources
* Independent Current Source forces a specific current to flow
through itself, independent of other elements in the circuit.
f=50

31. Chapter 1 Introduction 1.6.3 Current Sources
* Dependent (or Controlled) Current Sources
voltage-controlled current source, current-controlled current source

32. Chapter 1 Introduction
1.6.4 Resistors and Ohm’s Law

33. Chapter 1 Introduction
1.6.4 Resistors and Ohm’s Law

34. Chapter 1 Introduction
1.6.4 Resistors and Ohm’s Law

35. Chapter 1 Introduction
1.6.4 Resistors and Ohm’s Law

36. Chapter 1 Introduction
1.6.4 Resistors and Ohm’s Law

37. Chapter 1 Introduction 1.6.4 Resistors and Ohm’s Law
*Ohm’s Law: Resistance R:
* Conductance: *

38. Chapter 1 Introduction 1.6.5 Conductor, semiconductor, insulator
1.6.6 Power
* Power:

39. Chapter 1 Introduction 1.7 Circuit Basics
* Calculate the current, voltage, and power for each element

40. Chapter 1 Introduction
Example 1.6
use
arbitrary reference

41. Chapter 1 Introduction
Example 1.7: Using KVL, KCL, and Ohm’s Law to Solve a Circuit

42. Chapter 1 Introduction
Additional Notes

43. Additional Example – Find current and voltage

44. Chapter 1 Introduction Additional Example –
Using KVL, KCL, and Ohm’s Law to Solve a Circuit

45. Chapter 1 Introduction
Quiz: Determine the power absorbed (received) or supplied by elements C and D.
(1) Element C:
KVL (loop w/ B, C, D):
A power of 14W is supplied by element C.
(2) Element D:
KCL (node b):
A power of 12W is absorbed (received) by element D.

46. Chapter 1 Introduction
Quiz: Exercises 1.14 and 1.15

47. Chapter 1 Introduction

48. Chapter 2 Resistive Circuits
1. Solve circuits (i.e., find currents and voltages of interest) by combining resistances in series and parallel.
2. Apply the voltage-division and current-division
principles.
3. Solve circuits by the node-voltage technique.
4. Solve circuits by the mesh-current technique.
5. Find Thévenin and Norton equivalents and apply
source transformations.
6. Apply the superposition principle.
7. Draw the circuit diagram and state the principles
of operation for the Wheatstone bridge.

49. Chapter 2 Resistive Circuits
2.1 Series and parallel Resistances
2.1.1 Series Resistances

50. Chapter 2 Resistive Circuits
2.1.2 Parallel Resistances

51. Chapter 2 Resistive Circuits
Example 2.1 – Find equivalent resistance

52. Chapter 2 Resistive Circuits
Exercise 2.1 – Find equivalent resistance

53. Chapter 2 Resistive Circuits
2.2 Simple Network Analysis – Example Find all i, v, p

54. Chapter 2 Resistive Circuits
2.3 Voltage-Divider and Current-Divider Circuits
Voltage-division Principle Current-division Principle

55. Chapter 2 Resistive Circuits
Example 2.4

56. Chapter 2 Resistive Circuits
Example 2.5

57. Chapter 2 Resistive Circuits – Additional Example

58. Chapter 2 Resistive Circuits – Quiz: Find equivalent resistance

59. Chapter 2 Resistive Circuits
2.4 Node-Voltage Analysis
2.4.1 Basic Procedures
(1) Selecting the Reference Node
(one end of a voltage source is a good choice)
(2) Assigning Node Voltages
(Labeling the voltages at each of the other nodes)

60. Chapter 2 Resistive Circuits
2.4.1 Basic Procedures
(1) Selecting the Reference Node
(2) Assigning Node Voltages
(3) Finding Element Voltages in Terms
of the Node Voltage
Use KVL to determine element voltages

61. Chapter 2 Resistive Circuits
2.4.1 Basic Procedures
(1) Selecting the Reference Node
(2) Assigning Node Voltages
(3) Finding Element Voltages in Terms of the Node Voltage
Passive Reference Configuration

62. Chapter 2 Resistive Circuits
2.4.1 Basic Procedures
(1) Selecting the Reference Node
(2) Assigning Node Voltages
(3) Finding Element Voltages in Terms of the Node Voltage
(4) Writing KCL Equations

63. Chapter 2 Resistive Circuits
Quiz – Exercises2.12b
Find

64. Chapter 2 Resistive Circuits
Exercise 2.12b

65. Chapter 2 Resistive Circuits
Example 2.8 (Node-voltage Analysis)
Find