3.1: Electron Theory

3.1: Electron Theory

Structure and distribution of electrical charges within: atoms, molecules, ions, compounds; Molecular structure of conductors, semiconductors and insulators.

3.2: Static Electricity & Conduction

3.2: Static Electricity & Conduction

Static electricity and distribution of electrostatic charges; Electrostatic laws of attraction and repulsion; Units of charge, Coulomb's Law; Conduction of electricity in solids, liquids, gases
and a vacuum.

3.3: Electrical Terminology

3.3: Electrical Terminology

The following terms, their units and factors affecting them: potential difference, electromotive force, voltage, current, resistance, conductance, charge, conventional current flow, electron
flow.

3.4: Generation of Electricity

3.4: Generation of Electricity

Production of electricity by the following methods: light, heat, friction, pressure, chemical action,magnetism & motion.

3.5: DC Sources of Electricity

3.5: DC Sources of Electricity

Construction & basic chemical action of primary cells, secondary cells, lead acid cells, nickel cadmium cells, other alkaline cells; Cells connected in series & parallel; Internal resistance & its effect on a battery; Construction, materials & operation of thermocouples; Operation of photocells.

3.6: DC Circuits

3.6: DC Circuits

Ohms Law, Kirchoff's Voltage & Current Laws; Calculations using the above laws to find resistance, voltage & current; Significance of the internal resistance of a supply.

3.7: Resistance / Resistor

3.7: Resistance / Resistor

a) Resistance & affecting factors; Specific resistance; Resistor colour code, values & tolerances, preferred values, wattage ratings; Resistors in series & parallel; Calculation of total resistance using series, parallel & series parallel combinations; Operation & use of potentiometers & rheostats; Operation of Wheatstone Bridge;

b) Positive & negative temperature coefficient conductance; Fixed resistors, stability, tolerance & limitations, methods of construction; Variable resistors, thermistors, voltage dependent resistors;
Construction of potentiometers and rheostats; Construction of Wheatstone Bridge.

3.8: Power

3.8: Power

Power, work & energy (kinetic & potential); Dissipation of power by a resistor; Power formula; Calculations involving power, work & energy.

3.9: Capacitance / Capacitor

3.9: Capacitance / Capacitor

Operation and function of a capacitor; Factors affecting capacitance area of plates, distance between plates, number of plates, dielectric and dielectric constant, working voltage, voltage rating; Capacitor types, construction & function; Capacitor colour coding; Calculations of capacitance and voltage in series and parallel circuits; Exponential charge and discharge of a capacitor, time constants; Testing of capacitors.

3.10: Magnetism

3.10: Magnetism

a) Theory of magnetism; Properties of a magnet; Action of a magnet suspended in the Earth's magnetic field; Magnetisation & demagnetisation; Magnetic shielding; Various types of magnetic
material; Electromagnets construction and principles of operation; Hand clasp rules to determine: magnetic field around current carrying conductor;

b) Magnetomotive force, field strength, magnetic flux density, permeability, hysteresis loop, retentivity, coercive force reluctance, saturation point, eddy currents; Precautions for care & storage of magnets.

3.11: Inductance / Inductor

3.11: Inductance / Inductor

Faraday's Law; Action of inducing a voltage in a conductor moving in a magnetic field; Induction principles; Effects of the following on the magnitude of an induced voltage: magnetic field strength, rate of change of flux, number of conductor turns; Mutual induction; The effect the rate of change of primary current & mutual inductance has on Factors affecting mutual inductance: number of turns in coil, physical size of coil, permeability of coil, position of coils with respect to each other; Lenz's Law & polarity determining rules; Back emf, self induction; Saturation point; Principle uses of inductors.

3.12: DC Motor / Generator Theory

3.12 DC Motor / Generator Theory

Basic motor & generator theory; Construction & purpose of components in DC generator; Operation of, & factors affecting output and direction of current flow; Operation of, & factors affecting output power, torque, speed & direction of rotation of C motors; Series wound, shunt wound & compound motors; Starter Generator construction.

3.13: AC Theory

3.13: AC Theory

Sinusoidal waveform: phase, period, frequency, cycle; Instantaneous, average, root mean square, peak, peak to peak current values; Triangular/Square waves; Single / 3 phase principles.

3.14: Resistive (R), Capacitive (C) and Inductive (L)

3.14: Resistive (R), Capacitive (C) and Inductive (L)

Phase relationship of voltage and current in L, C & R circuits, parallel, series & series parallel; Power dissipation in L, C & R circuits; Impedance, phase angle, power factor & current calculations; True power, apparent power & reactive power calculations.

3.15: Transformers

3.15 Transformers

Transformer construction principles and operation; Transformer losses & methods for overcoming them; Transformer action under load & no-load conditions; Power transfer, efficiency, polarity markings; Primary & Secondary current, voltage, turns ratio, power, efficiency; Auto transformers.

3.16: Filters

3.16: Filters

Operation, application & uses of the following filters: low pass, high pass, band pass, band stop.

3.17: AC Generators

3.17: AC Generators

Rotation of loop in a magnetic field & waveform produced; Operation & construction of revolving armature & revolving field type AC generators; Single phase, two phase & three phase alternators;
Three phase star & delta connections advantages & uses; Calculation of line & phase voltages & currents; Calculation of power in a three phase system; Permanent Magnet Generators.

3.18: AC Motors

 

3.18: AC Motors

Construction, principles of operation and characteristics of. AC synchronous & induction motors both single & polyphase; Methods of speed control & direction of rotation; Methods of producing a rotating field: capacitor, inductor, shaded or split pole.

Get in touch

Fast Connect (Coming Soon)

  • Alumni
  • Downloads
  • Documents
  • Galleries