• # ETT Level 2.4: Electrical and Physical Theory

## Learn about the fundamentals of electricity and physical science.

1. Basic physical science - Apply terms, definitions, and concepts from mechanics, electricity, heat, and chemistry. (Solutions may involve simple formulas found in basis physics texts but will not involve algebraic manipulation or trigonometry.)
• Classical Mechanics Classical mechanics is concerned with the set of physical laws describing the motion of bodies under the influence of a system of forces.
• Basics of Electricity Electricity concerns the presence of electric charges, as well as the flow of those charges as an electric current.
• Heat and Temperature Knowing the difference between heat and temperature is important. It can lead to a clearer understanding of energy.
• Thermal Physics - Heat and Temperature Understand how the relative temperature of two objects affects the direction that heat is transferred between the two objects.
• Fundamentals of chemistry An introduction to the Periodic Table, stoichiometry, chemical states, chemical equilibria, acid & base, oxidation & reduction reactions, chemical kinetics, inogranic nomenclature and chemical bonding.
2. Fundamentals of electricity
Recognize and define the standard units used to describe electrical circuits, energy, and power. Apply Ohm's Law to simple circuits.
3. AC circuits
Identify series and parallel circuits and apply Ohms Law to simple single-loop ac circuits with linear components. Calculate equivalent capacitance and inductance. Measure and/or calculate impedance and power.
• Three-phase Power Systems A polyphase power system uses multiple voltage sources at different phase angles from each other (many "phases" of voltage waveforms at work). A polyphase power system can deliver more power at less voltage with smaller-gage conductors than single- or split-phase systems.
• Phase Relationships in AC Circuits Know Voltage Leads Current in an inductor (ELI) and Current Leads Voltage in a capacitor (ICE).
• Simple AC Circuit Calculations AC circuit calculations for resistive circuits are the same as for DC.
• AC Capacitor Circuits Capacitors oppose changes in voltage by drawing or supplying current as they charge or discharge to the new voltage level.
• AC Inductor Circuits Inductors oppose changes in current through them, by dropping a voltage directly proportional to the rate of change of current.
• Reactance And Impedance -- R, L, And C Impedance is a comprehensive expression of any and all forms of opposition to electron flow, including both resistance and reactance.
4. DC circuits
Identify series and parallel circuits and apply Ohm's Law to simple series dc circuits with linear nonreactive components. Calculate equivalent resistance of and power consumed by resistive devices.
• Series And Parallel Circuits Circuits consisting of just one battery and one load resistance are very simple to analyze, but they are not often found in practical applications. Usually, we find circuits where more than two components are connected together.
• Ohm's Law In this algebraic expression, voltage (E) is equal to current (I) multiplied by resistance (R). Using algebra techniques, we can manipulate this equation into two variations, solving for I and for R.
• Resistors Devices called resistors are built to provide precise amounts of resistance in electric circuits. Resistors are rated both in terms of their resistance (ohms) and their ability to dissipate heat energy (watts).

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