Siemens STEP 2000: Basics of Electricity

A set of vocabulary flashcards covering the concepts from the Siemens STEP 2000 Basics of Electricity course, including electron theory, circuit types, Ohm's Law, and electromagnetism.

STEP

Acronym for the Siemens Technical Education Program, designed to prepare distributors to sell Siemens Energy & Automation products effectively.

Electron

A subatomic particle orbiting the nucleus of an atom that carries a negative charge ($-$).

Proton

A subatomic particle located in the nucleus of an atom that carries a positive charge ($+$).

Neutron

A subatomic particle located in the nucleus of an atom that is electrically neutral.

Bound Electrons

Electrons that are held in their orbit by the attraction of the protons in the nucleus.

Free Electrons

Electrons in the outer band of an atom that can become free of their orbit through external forces like magnetic fields, friction, or chemical action; they are the basis of electricity.

Conductors

Materials that permit many electrons to move freely, such as copper, silver, aluminum, zinc, brass, and iron.

Insulators

Materials that allow very few free electrons to flow, such as plastic, rubber, glass, mica, and ceramic.

Semiconductors

Materials like silicon used to manufacture devices that can act as both conductors and insulators depending on the direction of the applied external force.

Electrically Neutral

The state of an atom when it contains an equal number of electrons and protons.

Positive Charge

Descriptive of a material or atom that has a lack or deficiency of electrons.

Negative Charge

Descriptive of a material or atom that has an excess of electrons.

Coulomb’s Law of Charges

States that charged bodies attract or repel each other with a force directly proportional to the product of the charges and inversely proportional to the square of the distance between them.

Current

The flow of free electrons in a conductor, designated by the symbol $I$ and measured in amperes.

Ampere (Amp)

The unit of measurement for current, symbolized by $A$, representing approximately $6.24 \times 10^{18}$ electrons moving through a cross-section of a conductor in one second.

Electron Flow Concept

The theory stating that electrons flow from the negative terminal ($-$) to the positive terminal ($+$).

Conventional Current Flow Theory

A theory that ignores electron flow and states that current flows from the positive terminal ($+$) to the negative terminal ($-$).

Voltage

The force applied to a conductor that causes electric current to flow, also known as electromotive force (emf) or potential difference; designated by symbols $E$ or $V$.

Resistance

The property of a material to impede the flow of electrical current, designated by the symbol $R$ and measured in ohms ($\Omega$).

Ohm’s Law

A law formulated by George Simon Ohm stating that current varies directly with voltage and inversely with resistance, expressed as $I = \frac{E}{R}$.

Series Circuit

A circuit formed when resistors are connected end-to-end so there is only one path for current to flow; total resistance is the sum of all individual resistances ($R_t = R_1 + R_2 + ...$).

Kirchhoff’s Law (Voltage)

States that the sum of the voltage drops across the resistances of a closed circuit equals the total voltage applied to the circuit.

Parallel Circuit

A circuit formed when two or approximation resistances are placed side-by-side so current can flow through more than one path; voltage is the same across each branch.

Power

The rate at which work is done in an electrical circuit, represented by the symbol $P$ and measured in watts ($W$).

Watt

The unit of power, defined as the rate at which work is done when $1\,A$ flows with $1\,V$ applied ($P = E \times I$).

Magnetic Lines of Flux

Invisible lines of force that leave the north pole of a magnet and enter the south pole, always forming closed loops.

Left-Hand Rule for Conductors

States that if a current-carrying conductor is grasped with the left hand and the thumb points in the direction of electron flow, the fingers will point in the direction of the magnetic lines of flux.

Electromagnet

A device composed of a coil of wire wound around a core (usually soft iron) that becomes magnetized when current passes through the coil.

Alternating Current (AC)

A type of electricity where electrons flow first in one direction and then the other as the generator reverses terminal polarity.

Sine Wave

The graphic representation of AC showing how voltage or current varies continuously over time.

Cycle

One complete 360-degree rotation of an AC sine wave.

Hertz (Hz)

The unit of measurement for frequency, representing cycles per second; in the United States, AC is typically generated at $60\,Hz$.

Three-Phase Power

A continuous series of three overlapping AC cycles, each offset by $120$ electrical degrees, used for large commercial and industrial applications.