BSC102C

Unit Description and General Aims

The objective of this unit is to familiarise the students with the various elements of electrical circuits and the behaviour of circuits when connected to a power source. Information covered in this unit will include: the fundamentals of DC and AC circuits; the measurement of voltage, current, power, resistance; and, other basic electrical concepts. Additionally, the various circuit combinations, mathematical methods for resolving DC and AC circuits, calculations for AC circuits involving the use of complex numbers in Cartesian and polar forms, the use of various circuit theorems, the maximum power transfer theorem, and the basics of resonance and harmonics in complex waveforms, will also be discussed.

Learning Outcomes

On successful completion of this Unit, students are expected to be able to:

1. Explain the different passive components found in electrical circuits and their behaviour.
   Bloom’s Level 3
2. Perform calculations involving simple circuits in DC networks including the behaviour under sudden voltage change conditions.
   Bloom’s Level 3
3. Explain the behaviour of passive components in AC circuits powered by single phase AC supply.
   Bloom’s Level 3
4. Perform calculations in AC circuits using polar and Cartesian systems (involving complex numbers) and applying various circuit theorems to solve complex networks.
   Bloom’s Level 3
5. Explain the analysis of complex waveforms and analyse the frequency components in commonly encountered non-sinusoidal waveforms using numerical methods.
   Bloom’s Level 3
6. Discuss the principles of measurement of electrical parameters using electrical instruments, bridges, and applications of electromagnetism.
   Bloom’s Level 3

Student assessment

Prescribed and Recommended readings

Suggested Textbook

• Bird John, 2013, Electric Circuit Theory and Technology, Newnes (Elsevier Science), ISBN 978-0415662864

Reference Materials

• Circuit Theory, 2013, wikibooks.org
  (download link: http://upload.wikimedia.org/wikipedia/commons/f/f8/Circuit_Theory.pdf)
• Peer reviewed Journals
• Knovel library: http://app.knovel.com
• IDC Technologies publications
• Other material and online collections as advised during the lectures

Unit Content

Topic 1

Electrical quantities, resistance in DC circuits

1. Units of electrical measurements
2. Electric charges, forces and fields
3. Coulomb’s Law
4. Electricity – electric field, potential, potential difference, and current
5. Conductors and insulators
6. Introduction to circuits and Ohm’s law
7. Resistance and its variation with temperature
8. Different types of resistances and their comparison
9. Solving combinations of series and parallel circuits
10. Kirchhoff’s Law and its application in DC circuits
11. Voltage and current division in series/parallel circuits

Topic 2

Electromagnetism and its applications

1. The relation between current and flux produced by a conductor
2. The principle of flux linkage inducing a voltage in a coil
3. The relation between current, flux, and force on a conductor
4. Fleming’s rules
5. Application in electrical machines and transformers

Topic 3

Capacitance and capacitors

1. Capacitance
2. Parallel plate capacitor
3. Dielectric strength and permittivity
4. Electrostatic field and field strength
5. Series/parallel circuits with capacitive elements
6. Behaviour of capacitors for step variations in DC voltage
7. Energy stored in capacitive components
8. Need for discharging of capacitors to discharge stored energy
9. Different types of capacitors and applications
10. Construction of a practical capacitor and capacitance marking

Topic 4

Inductance and inductors

1. Inductance
2. Construction of an inductor
3. MMF/Ampere turns
4. Flux and flux density
5. Permeability and reluctance in a magnetic core
6. B-H curve and saturation
7. Hysteresis
8. Behaviour of inductances for step variations in DC voltage
9. Energy storage in inductive components
10. Need for discharging of inductances to discharge stored energy  

Topic 5

AC circuits

1. AC waveform characteristics and mathematical expression (amplitude/time relationship)
2. Peak and RMS values and calculation of crest (peak) factor and form factor for pure sine wave using mathematical methods
3. Purely resistive circuits: voltage/current relationships
4. Purely inductive circuits and the concept of inductive reactance
5. Voltage/current relationships in inductive AC circuits
6. Saturation and the behaviour of inductance upon saturation in an AC circuit
7. Hysteresis associated with AC supply and hysteresis loss
8. Purely capacitive circuits: Capacitive reactance, series and parallel capacitor calculations
9. Voltage/current phase relationships of capacitive AC circuits
10. Dielectric loss and loss angle in a capacitor

Topic 6

Solving AC circuits using polar and Cartesian coordinates principles

1. Introduction to phasors and polar coordinates
2. Expressing an AC voltage waveform using polar coordinates
3. Using polar coordinate system to explain voltage/current relationship of an inductor
4. Using polar coordinate system to explain voltage/current relationship of a capacitor
5. Calculation of impedance of AC circuits using polar coordinates in series and parallel circuits
6. Voltage/current/impedance relationship using polar representation
7. Use of Cartesian coordinates to express voltage and current in AC circuits
8. Introduction to complex algebra and the operator ‘i’
9. Conversion between polar and Cartesian coordinates
10. Cartesian coordinates to represent AC circuits using complex notation
11. Concept of impedance in AC circuits and voltage/current calculations using an impedance
12. Power in AC circuits and the concept of power factor to calculate useful power
13. Power Triangle

Topic 7

Solving AC circuits using complex numbers

1. Expressing an AC voltage waveform using complex numbers
2. Using complex numbers to explain voltage/current relationship of an inductor
3. Using complex numbers to explain voltage/current relationship of a capacitor
4. Calculation of impedance of AC circuits using complex numbers in series and parallel circuits
5. Voltage/current/impedance relationship using complex numbers
6. Use of complex numbers to express voltage and current in AC circuits with a mix of components

Topic 8

Circuit theorems applied to AC circuits

1. Constant voltage source
2. Constant current source
3. Kirchhoff’s Law as applied to AC circuits
4. The Superposition Theorem
5. Thevenin’s Theorem
6. Norton’s Theorem
7. Thevenin and Norton equivalent networks
8. Example calculations

Topic 9

Circuit theorems applied to AC circuits

1. Maximum Power Transfer Theorem
2. Impedance matching
3. Delta-star transformation for circuit reduction
4. Mesh current analysis in AC circuits
5. Nodal analysis
6. Example calculations

Topic 10

Electrical measurements

1. Measurement using instruments-Basic galvanometer principle
2. Analogue instruments using moving coil/moving iron principle
3. Use of shunts and multipliers
4. Ohm metres and power metres
5. Digital instruments and their principle
6. Loading effect of instruments and errors introduced
7. Oscilloscope as measuring device
8. Potentiometers
9. Bridges and their use in measurements

Topic 11   

Complex waveforms, harmonics and resonance

1. General equation for a complex waveform
2. Harmonic synthesis
3. RMS, Mean and form factor for complex waveforms
4. Power associated with harmonic components
5. Sources of harmonics
6. Resonance in AC circuits-definition
7. Series resonance
8. Parallel resonance
9. Q factor
10. Voltage magnification
11. Resonance due to harmonics

Topic 12

Unit Review

In the final week students will have an opportunity to review the contents covered so far. Opportunity will be provided for a review of student work and to clarify any outstanding issues. Instructors/facilitators may choose to cover a specialized topic if applicable to that cohort.

Software/Hardware Used

Software

• Software: National Instruments ELVISmx Instrument Launcher  ( on Remote Lab); National Instruments Multisim  ( on Remote Lab)
• LTSpice - free SPICE simulator software
• Version: N/A
• Instructions:  N/A
• Additional resources or files: N/A

Hardware

• National Instruments MyDAQ  (on Remote Lab)