Electrical Engineering Definitions: Atomic Physics, Circuits, and Measurements

A complete set of vocabulary flashcards covering basic atomic and material physics, electrical properties and laws, SI and imperial units of measurement, circuit components, circuit network topologies, and electrical measurement instruments.

Matter

Anything that possesses mass and occupies physical space.

Element

A pure chemical substance consisting entirely of one type of atom, distinguished by its atomic number.

Compound

A substance formed when two or more distinct chemical elements are chemically bonded together in a fixed ratio.

Molecule

The smallest fundamental unit of a chemical compound that can take part in a chemical reaction; it consists of two or more atoms bonded together.

Atom

The basic building block of ordinary matter and the smallest unit of an element that retains the properties of that element.

Proton

A stable subatomic particle found in the nucleus of an atom, carrying a positive electric charge.

Electron

A subatomic particle with a negative elementary electric charge, orbiting the nucleus and acting as the primary carrier of electricity in solids.

Neutron

A subatomic particle of about the same mass as a proton but without an electric charge, located in the atomic nucleus.

Nucleus

The small, dense, positively charged region at the center of an atom, consisting of protons and neutrons.

Valence Electrons

The electrons located in the outermost electron shell of an atom that participate in chemical bonding and electrical conduction.

Atomic Number

The number of protons found in the nucleus of an atom, which determines the chemical properties of an element and its place in the periodic table.

Atomic Mass

The total mass of protons, neutrons, and electrons in a single atom, typically expressed in atomic mass units (amu).

Mass of an Electron

The rest mass of an electron, approximately $9.109 \times 10^{-31}\,\text{kg}$ (roughly $1/1836$ the mass of a proton).

Mass of a Proton

The rest mass of a proton, approximately $1.672 \times 10^{-27}\,\text{kg}$.

Mass of a Neutron

The rest mass of a neutron, approximately $1.675 \times 10^{-27}\,\text{kg}$, making it slightly heavier than a proton.

Electricity

A broad class of physical phenomena arising from the existence, interaction, and movement of electric charge, encompassing concepts like electric current, static electricity, and electromagnetic fields.

Electric Charge

The physical property of matter (positive or negative) that causes it to experience a force when placed in an electromagnetic field.

Potential Difference

The difference in electrical potential energy between two points, representing the work required to move a charge from one point to another.

Work

The transfer of energy that occurs when a force is applied over a distance; in electrical terms, it is the energy required to move a charge across a potential difference.

Electric Current

The rate of flow of electric charge past a point or region in a conductive medium.

Resistance

The measure of opposition that a material or component offers to the continuous flow of electric current.

Resistivity

An intrinsic material property that quantifies how strongly a specific material opposes the flow of electric current, independent of its shape or size.

Temperature Coefficient of Resistance

A material property that quantifies how much its electrical resistance changes with a change in temperature, usually expressed as the fractional change in resistance per degree Celsius (or Kelvin). A positive coefficient means resistance increases as temperature rises, while a negative coefficient means resistance decreases as temperature rises.

Electromotive Force (EMF)

The energy supplied by a non-electrical source (like a battery or generator) per unit charge, driving electrons through a circuit.

Voltage

The pressure from a circuit's power source that pushes charged electrons through a conducting loop, enabling them to do work.

Ohm's Law

A fundamental principle stating that the current through a conductor between two points is directly proportional to the voltage across those points ($V = IR$).

Electrical Power

The rate per unit time at which electrical energy is transferred, converted, or dissipated by an electric circuit.

Energy

The quantitative capacity to do work or produce heat; in electricity, it is the total power consumed or generated over time.

Coulomb

The SI unit of electric charge, equal to the quantity of charge conveyed in one second by a current of one ampere.

Volts

The SI unit of electromotive force and electrical potential difference.

Amperes

The SI unit of electric current, representing a flow of one coulomb of charge per second.

Ohms

The SI unit of electrical resistance.

Watts

The SI unit of power, equivalent to one joule per second.

Horsepower

A standard unit of mechanical power; in electrical conversions, one horsepower is equal to exactly $746\,\text{watts}$.

Joules

The SI unit of work or energy, equal to the work done by a force of one newton displacing an object by one meter.

Calorie

A unit of energy defined as the amount of heat required to raise the temperature of one gram of water by $1^\circ\text{C}$.

BTU (British Thermal Unit)

A traditional unit of heat energy, defined as the amount of heat required to raise the temperature of one pound of water by $1^\circ\text{F}$.

Electrical Circuit

A closed, continuous path that allows electric current to flow from a source through various components and back.

Switch

An electrical device used to intentionally interrupt or complete the flow of electrons in a circuit.

Wire

A flexible, cylindrical strand of conductive metal used to carry electric current between components.

Source

The active component or element in a circuit that supplies electrical energy (e.g., a battery, solar panel, or AC generator).

Resistor

A passive electrical component designed to introduce a specific amount of electrical resistance into a circuit to limit current or divide voltage.

Capacitor

A passive component that stores electrical energy in an electrostatic field by separating opposite charges on two conductive plates.

Inductor

A passive component, typically a coil of wire, that stores energy in a magnetic field when electric current flows through it.

Parallel Circuit

A circuit configuration where components are connected across the same two nodes, ensuring the same voltage is applied to all components while current splits among branches.

Series Circuit

A circuit configuration where components are connected end-to-end in a single path, meaning the exact same current flows through every component sequentially.

Series-Parallel Circuit

A hybrid circuit configuration where multiple parallel-connected branches are themselves connected in series with other components or branches.

Parallel-Series Circuit

A hybrid circuit configuration where multiple series-connected strings of components are connected in parallel across a common voltage source or set of nodes.

Delta Connection

A three-phase electrical wiring configuration where the ends of the three phases are connected in a closed, triangle-like loop (high reliability, no neutral wire).

Wye Connection

A three-phase electrical wiring configuration where one end of each phase connects at a common central node, forming a "Y" shape (allows for a neutral wire and multiple voltage levels).

Ohmmeter

An instrument used to directly measure the electrical resistance of a component or circuit.

Ammeter

An instrument connected in series to measure the electric current flowing through a circuit.

Voltmeter

An instrument connected in parallel to measure the electrical potential difference between two specific points in a circuit.

Wattmeter

An instrument used to measure the active electrical power (in watts) being consumed or generated by a circuit.