Electrical Fundamentals

The building blocks of aviation electricity - the composition of matter, the structure of the atom, electron shells and energy levels, and why materials behave as conductors, insulators or semiconductors.

How electrical charge behaves at rest - the build-up and distribution of electrostatic charges, attraction and repulsion, Coulomb's Law, and conduction through solids, liquids, gases and a vacuum.

The language of electrical systems - SI prefixes, conventional and electron flow, electromotive force, voltage, current, resistance and the relationships used in aircraft maintenance calculations.

How electricity is produced - by friction, pressure through the piezoelectric effect, heat with thermocouples, light in photovoltaic cells, chemical action in cells and magnetism and motion in generators.

The direct-current sources that power an aircraft - primary and secondary cells, lead-acid and nickel-cadmium batteries, their ratings, testing and charging, plus thermocouples and photo-cells.

The practical rules for analysing direct-current circuits - Ohm's Law, Kirchhoff's voltage and current laws, voltage dividers, parallel branches and series-parallel networks.

How resistance is created, measured and controlled - conductor properties, wire sizing, resistor construction, colour codes, variable resistors, thermistors, photo-conductive cells and Wheatstone bridges.

The relationship between power, work and energy in aircraft electrical systems - power formulas, resistor dissipation, series and parallel networks, horsepower and energy consumption over time.

How capacitors store and release electrical energy - plate construction, dielectrics, types, RC time constants, series and parallel combinations, capacitive reactance and testing.

The magnetic principles used throughout aircraft electrical equipment - magnetic fields, materials, magnetisation, electromagnets, hysteresis, eddy currents, magnetic shielding and safe storage.

How changing magnetic fields induce voltage - Faraday's and Lenz's Laws, self and mutual induction, back EMF, RL time constants, inductor combinations and inductive reactance.

The construction and operation of DC generators and motors - armatures, fields, commutators, winding types, torque, speed, counter EMF, maintenance and starter-generator systems.

The foundations of alternating current - sinusoidal generation, cycles, frequency, period, wavelength, phase, instantaneous and RMS values, non-sinusoidal waves and single- and three-phase systems.

How resistance, capacitance and inductance behave in AC circuits - impedance, phase angle, series and parallel networks, resonance, power factor and true, apparent and reactive power.

The principles and applications of transformers - mutual induction, turns ratios, load and no-load behaviour, losses, efficiency, polarity, three-phase power, current transformers and autotransformers.

How passive filters select or reject frequency ranges - the filtering characteristics of capacitors and inductors and the operation of low-pass, high-pass, band-pass and band-stop networks.

How alternators and generator control systems produce and regulate aircraft AC power - rotating loops, excitation, phases, star and delta connections, brushless systems, protection, constant-speed drives and inverters.

The construction, operation and control of AC motors - rotating magnetic fields, induction and synchronous motors, single-phase starting methods, direction and speed control, series motors and maintenance.