EE Terms & Electrical Engineering Fundamentals Review

Comprehensive vocabulary flashcards covering fundamental electrical engineering definitions, network theorems, electromagnetic concepts, electrical machines, transformers, power systems, transmission, and protective relays.

Ampere-Hour

A unit of electric charge, commonly used to rate battery capacity.

Electric Current

The rate of flow of charge past a specific point per unit time, measured in coulombs per second ($\text{C/s}$) or amperes ($\text{A}$).

Resistivity

The intrinsic material property that opposes the flow of electric current, measured in ohm-meters ($\Omega \, \text{m}$).

Electric Power

The rate at which electrical energy is transferred or consumed, measured in watts ($\text{W}$) or joules per second ($\text{J/s}$).

Conductivity

The measure of a material's ability to conduct an electric current, equal to the reciprocal of resistivity and expressed in $(\Omega \, \text{m})^{-1}$.

Junction (Circuit Node)

A point in an electrical network where three or more circuit branches or wires are joined together.

Kirchhoff's Current Law (KCL)

The principle stating that the algebraic sum of currents entering a junction equals the sum of currents leaving that junction, derived directly from the conservation of charge.

Kirchhoff's Voltage Law (KVL)

The law stating that the algebraic sum of all electromotive forces (emfs) and potential differences around any closed circuit loop is zero, derived from the conservation of energy.

Wire-Gauge

A standardized measuring device used to determine the diameter of an electrical wire.

Temperature Coefficient of Resistance

The fractional change in resistance per ohm of a material per degree change in temperature.

Maximum Power Transfer Theorem

A circuit theorem stating that maximum power is transferred from a source to a load when the load resistance equals the internal resistance of the source, operating at a transmission efficiency of $50\%$.

Ideal Current Source

A theoretical circuit element that supplies a constant current independent of the voltage across its terminals, having an infinite internal resistance.

Norton's Theorem

A network analysis theorem stating that any linear two-terminal DC network can be replaced by an equivalent circuit consisting of an independent current source in parallel with an equivalent resistor.

Millman's Theorem

A circuit analysis theorem that allows multiple parallel voltage or current sources to be combined directly into a single equivalent voltage or current source.

Superposition Theorem

A principle applicable exclusively to linear circuits, stating that the response in any branch is the algebraic sum of the responses caused by each independent source acting alone.

Helmholtz Coils

A pair of identical circular coaxial coils separated by a distance equal to their radius $R$, used to produce an exceptionally uniform magnetic field between them.

Weber ($\text{Wb}$)

The SI unit of magnetic flux, equivalent to one volt-second ($1 \, \text{V} \cdot \text{s}$).

Henry ($\text{H}$)

The SI unit of inductance, equivalent to one volt-second per ampere ($1 \, \text{V} \cdot \text{s} / \text{A}$).

Tesla ($\text{T}$)

The SI unit of magnetic flux density (or magnetic field density), equivalent to one weber per square meter ($1 \, \text{Wb} / \text{m}^2$).

Permeability

The property of a material representing its ability to conduct magnetic flux lines through itself.

Displacement Current

A quantity appearing in Maxwell's equations that exists in a region where an electric field is changing with time.

Lenz's Law

The fundamental law stating that the direction of an induced electromotive force and current will always oppose the change in magnetic flux that produces them.

Growler

An electromagnetic diagnostic device used primarily to detect short-circuited coils in motor and generator armatures.

Electron Volt ($\text{eV}$)

A unit of energy equal to the work done or energy gained by an electron when moving through an electric potential difference of 1 volt ($1 \, \text{V}$).

Farad ($\text{F}$)

The SI unit of capacitance, defined as one coulomb per volt ($1 \, \text{C/V}$) or equivalently $\text{C}^2 / \text{J}$.

Gauss's Law

The physical law stating that the total electric flux passing through any closed surface is proportional to the total net electric charge enclosed within that surface.

Root Mean Square (RMS) Current

The effective value of an alternating current, equivalent to the steady direct current that produces the exact same rate of resistive heating.

Pole Pitch

The peripheral distance or space on the stator frame allocated to one magnetic pole.

Full-Pitch Winding

An armature winding configuration where the span between coil sides is exactly equal to one pole pitch.

Synchronous Speed ($N_s$)

The rotational speed of the stator magnetic field in an AC machine, calculated using the formula $N_s = \frac{120f}{P}$, where $f$ is frequency and $P$ is the number of poles.

Synchronous Condenser

A synchronous motor operated without a mechanical shaft load, whose field excitation is adjusted specifically for power factor correction.

Lambert's Cosine Law

The optical law stating that the illumination received by a surface is directly proportional to the cosine of the angle between the surface normal and the incident luminous flux.

Hysteresis Loss

The electrical power dissipated as heat in a magnetic core due to repeated cyclic magnetization and demagnetization of the ferromagnetic material.

Autotransformer

A transformer containing only a single continuous winding that serves simultaneously as both primary and secondary circuits.

Conservator (Transformer)

An airtight drum mounted atop an oil-immersed transformer tank to provide expansion space and store oil during thermal volume changes.

Breather (Transformer)

An auxiliary transformer component containing a desiccant designed to extract moisture from atmospheric air entering the conservator tank.

Magnetostriction

The physical phenomenon causing ferromagnetic material to alter its dimensions in response to varying magnetic flux, responsible for audible transformer hum.

Load Factor

The ratio of the average electrical load over a given time interval to the maximum peak load occurring during that same period.

Surge Tank

A protective water reservoir located along a hydroelectric penstock designed to absorb and relieve destructive water hammer pressure transients.

Spinning Reserve

The unused generating capacity in an active power station that is synchronized to the bus and immediately available to take on load.

Transposition

The practice of rotating or interchanging conductor physical positions at periodic distances along a transmission line to balance mutual inductances and eliminate phase imbalances.

ACSR Conductor

Aluminum Conductor Steel Reinforced; an overhead transmission cable consisting of outer strands of high-conductivity aluminum layered around a high-strength galvanized steel core.

Armouring

A protective outer layer of steel tape or wire wrapped around an underground cable to safeguard it against mechanical injury during handling and laying.

Skin Effect

The tendency of an alternating current to concentrate near the outer surface of a conductor, thereby reducing the effective cross-sectional area and increasing AC resistance.

Ferranti Effect

The phenomenon occurring on lightly loaded or unloaded long transmission lines where the receiving-end voltage exceeds the sending-end voltage due to line charging capacitance.

Differential Protective Relay

A protective relay operating on the principle of Kirchhoff's Current Law that compares currents entering and leaving a protected zone to isolate internal faults.

Mho Relay

A directional distance relay with an admittance operating characteristic widely used for the protection of high-voltage transmission lines.

Corona

The dielectric breakdown and ionization of air surrounding a high-voltage conductor, accompanied by a hissing sound, violet glow, and radio interference.

Fault Level

The prospective short-circuit power at a designated point in an electrical network, expressed in fault megavolt-amperes ($\text{MVA}$).

Circuit Recloser

An automated protective switching device designed to interrupt a circuit and automatically reclose several times to clear transient line faults or lockout permanently on persistent faults.

Ground Fault Circuit Interrupter (GFCI)

A fast-acting circuit protection device designed to de-energize a circuit when an imbalance between supply and return currents indicates dangerous leakage current to ground.

Buchholz Relay

A gas-actuated safety device installed in the pipe between an oil-filled transformer tank and its conservator to detect internal faults and insulation breakdown.