Electrical Network Analysis Quiz

Applied Electricity Lecture Notes

Course Instructor: Solomon Nunoo
University: University of Mines and Technology, Tarkwa
Date: August, 2010
Course: Electrical and Electronic Engineering
Course Number: EL, MC 151

Chapter 1: Circuit Laws

1.1 Introduction: Electric circuits consist of interconnected circuit elements, including voltage and current sources. Constraints between currents and voltages, along with element relationships, provide network solutions.
1.2 Ohm's Law: Current (I) in a circuit is directly proportional to voltage (V) provided temperature remains constant. I = V/R, where R is resistance.
1.3 Kirchhoff's Voltage Law (KVL): For any closed path in a network, the algebraic sum of the voltages is zero.
1.4 Kirchhoff's Current Law (KCL): The algebraic sum of currents entering a node is equal to the sum of currents leaving that node.
1.5 Circuit Elements in Series: Passive elements in series carry the same current. Total voltage is the sum of individual voltages across each element. Series resistors add up: Req = R₁ + R₂ + ... + Rn.
1.6 Circuit Elements in Parallel: Elements in parallel have the same voltage. Total current is the sum of individual currents through each element. Parallel resistors have an equivalent resistance 1/Req = 1/R1 + 1/R2 + ... + 1/Rn.
1.7 Voltage Division: In a series circuit, the voltage across a resistor is proportional to its resistance compared to the total resistance.
1.8 Current Division: In a parallel circuit, the current through a branch is inversely proportional to its resistance compared to resistances in the other branches.
1.9 Network Reduction: Combining series and parallel components to reduce complex circuits.
1.10 Electrical Power and Energy: Power (P) = Voltage (V) × Current (I). Electrical Energy = Power × Time.
1.11 Problems: Includes various circuit analysis problems applying Ohm's law, KVL, and KCL.
1.11.1 Ohm's Law: Problems calculating resistance given voltage and current.
1.11.2 Kirchhoff's Laws: Problems calculating currents in various circuit configurations using Kirchoff's laws .
1.11.3 Power and Energy: Problems involving calculation of power dissipated in circuit elements.

Chapter 2: Circuit Theorems (Analysis Methods)

2.1 The Branch Current Method: Assigns currents to branches of a network and relates them to voltages between nodes.
2.2 Mesh Current Method: Assign currents to each loop, then write KVL equations for each loop.
2.3 Node Voltage Method: Selects a reference node and expresses currents at other nodes in terms of voltages.
2.4 Superposition Theorem: Analyze a network with multiple sources by finding the response due to each source independently and summing the resulting responses.
2.5 Thévenin's and Norton's Theorems: Represent complex networks by simpler equivalent circuits containing a voltage source and series resistance (Thévenin) or a current source and parallel resistance (Norton), useful for analyzing and simplifying complex circuits.
2.6 A-Y and Y-Δ Conversions: Converting a Delta (Δ) network to a Wye (Y) network, and vice versa to simplify circuit analysis.
2.7 Problems: A set of problems applying the theorems and conversions.

Chapter 3: Capacitors and Capacitance

3.1 Electrostatic Field: Charged plates have a field between them
3.2 Electric field strength: Related to the voltage and distance between the plates.
3.3 Capacitance: The ability of two conductors to store an electric charge.
3.4 Capacitors: Devices specially designed for capacitance.
3.5 Electric Flux Density: Amount of flux passing through a given area.
3.6 Permittivity: Ratio of flux density to electric field strength measured in a medium.
3.7 The Parallel Plate Capacitor: Describes the capacitance of parallel plate capacitors.
3.8 Capacitors Connected in Parallel and Series: Explains how to combine capacitors for parallel and series combinations.
3.9 Dielectric Strength: Maximum electric field strength a dielectric material can withstand without breaking down.
3.10 Energy Stored: Energy stored in a capacitor.
3.11 Practical Types of Capacitor: Different types of capacitors (variable air, mica, paper, ceramic, plastic, titanium oxide and electrolytic).
3.13 Problems: A set of problems covering the topics covered in the chapter.

Chapter 4: Magnetic Circuits

4.1 Magnetic Fields: Magnetic flux distribution around a magnet (or magnetic material).
4.2 Magnetic Flux and Flux Density: The amount of magnetic lines of force. Magnetic flux density is flux per unit area.
4.3 Magnetomotive Force and Magnetic Field Strength: Cause of flux in a magnetic circuit; measured in ampere-turns.
4.4 Permeability and B-H Curves: Relation of flux density (B) and magnetic field strength (H). The B-H curve for various magnetic materials is presented.
4.5 Reluctance: The resistance to flux in a magnetic circuit.
4.6 Composite Series Magnetic Circuits: Combining reluctances in series.
4.7 Comparison between Electrical and Magnetic Quantities: Electrical and Magnetic circuit quantities comparison (emf, current, flux, resistance etc.).
4.8 Hysteresis and Hysteresis Loss: Lagging of flux density behind changes in magnetic field.
4.9 Problems: A set of problems involving the calculation of magnetic field strength, flux density, and reluctance.

Chapter 5: Electromagnetism

5.1 Magnetic Field due to an Electric Current: Describes how an electric current produces a magnetic field.
5.2 Electromagnets: Devices that use a coil of wire to create a magnetic field to attract iron or steel.
5.3 Force on a Current-Carrying Conductor: Force exerted on a current carrying conductor in a magnetic field
5.5 Problems: Problems involving the application of the principles of electromagnetism, including calculating the force on a current-carrying conductor and on a moving charge.

Chapter 6: Electromagnetic Induction

6.1 Introduction: How a changing magnetic field induces an ecmf in a conductor.
6.2 Laws of Electromagnetic Induction: Faraday's law and Lenz's Law.
6.3 Inductance: Self inductance and mutual inductance.
6.4 Inductors: Devices used in circuits to introduce inductance.
6.5 Energy Stored: Energy stored in an inductor .
6.7 Mutual Inductance: Emf induced in a second circuit by changing current in the first circuit.
6.8 Problems: Problems related to induced e.mf and inductance.

Chapter 7: Alternating Current Theory

7.1 Introduction: Basics of alternating waveforms.
7.2 The AC Generator: How AC is generated in a rotating magnetic field.
7.3 Waveforms: Different types of alternating waveforms.
7.4 AC Values: Instantaneous, peak, average, RMS values.
7.5 Equation of a Sinusoidal Waveform: The mathematical relationship of alternating waveforms.
7.6 Combination of Waveforms: Combining alternating quantities.
7.7 Rectification: Process of converting AC to DC.
7.8 Problems: Problems involving the calculation of AC values and waveforms.

Chapter 8: Fundamentals of Alternating Current Circuits

8.1 AC Through Resistance, Inductance, and Capacitance: Phase relationships among voltage, current, resistance, inductance, and capacitance in AC circuits.
8.2 Series AC Circuits: Analysis of series AC circuits.
8.3 Parallel AC Circuits: Analysis of parallel AC circuits .
8.4 Power Factor Improvement: Methods to improve power factor in AC circuits.
8.5 Problems: Problems related to AC circuit analysis.

Chapter 9: Signal Waveforms

9.1 Introduction: Basic concepts of signal waveforms.
9.2 Step Function: Mathematical representation of a step input.
9.3 The Impulse: Mathematical representation of an impulse.
9.4 Ramp Function: Mathematical representation of a ramp input.
9.5 Sinusoidal function: A continuous time signal like voltage(v) and current(i).
9.6 Decaying Exponential: Describes how quantities decay exponentially over time
9.7 Time Constant: A characteristic time for exponential phenomena.
9.8 DC Signal: Constant-valued signal.

Chapter 10: Introduction to Electrical Machines

10.1 Introduction: Overview of AC/DC generation, transmission, and distribution.
10.2 Transformers: Types and operation of transformers (core/shell type).
10.2.1 Constructional Features: Details of transformer construction.
10.2.2 Principle of Operation: Explanation of transformer principle of operation.
10.3 DC Machines: Types and characteristics (separately excited, shunt, series, and compound).
10.3.1 Constructional Features: Details of DC generator/motor components.
10.3.2 Principle of Operation: Explanation of working of a DC generator/motor.
10.3.3 Emf Equations: Equations for calculating induced e.mf.
10.3.4 Characteristics: Various characteristics of DC machines.
10.3.5 Types: Classification of DC generators/motors.
10.3.6 Principle of Operation of DC Motors: How DC motors function.
10.3.7 Torque Equation: Equation for torque in a DC motor.
10.3.8 Characteristics (shunt, series, compound): Different operation characteristics of the respective DC motors type.
10.4 Induction Motors: Types (squirrel-cage, wound rotor/slip ring).
10.4.1 Construcitonal Features: Details of induction motor construciton.
10.4.2 Principle of Operation: How an induction motor function.
10.4.3 Torque Development: Calculation of the torque
10.4.4 Single-Phase Induction Motors: Methods of starting (capacitor start, capacitor start & run, shaded-pole).
10.5 Synchronous Machines: Operation and applications.
10.5.1 Constructional Features: Details of synchronous generator/motor.
10.5.2 Principle of Operation: How synchronous generators function.
10.5.3 Emf Equation: Calculations of e.mf
10.5.4 Load Characteristics: How the output characteristics change with load conditions.