Unit 8: Electricity, Electrostatics, and Magnetism

Vocabulary flashcards covering electrical concepts, quantities, units, circuit configurations, and measurement devices from Unit 8.

Current

The flow of charged particles, usually electrons, represented by the variable $I$ and measured in amperes or amps ($\text{A}$).

Voltage (Potential Difference)

The measure of electrical potential energy per unit charge (joules per coulomb, where $1\,\text{C} = 6.25 \times 10^{18}\text{ electrons}$), represented by $\Delta V$ or $V$ and measured in volts ($\text{V}$).

Resistance

The measure of how much an object or material opposes the flow of electric current, represented by the variable $R$ and measured in ohms ($\Omega$).

Conductor

A material that permits electrons to flow freely from particle to particle.

Insulator

A material that impedes the free flow of electrons from atom to atom and molecule to molecule.

Ohm's Law

The physical law stating that current equals the voltage divided by the resistance ($I = \frac{V}{R}$ or $V = IR$).

Electric Power

The rate of electrical energy transfer, calculated as the current multiplied by the potential difference ($P = VI$) and measured in watts ($\text{W}$).

Circuit Breaker

An automatic electrical switch designed to protect a circuit from damage caused by overloads or shorts by switching to the off position when there is excess current.

Series Circuit

A circuit configuration where electricity flows from one device to the next in order along a single path with no split points (junctions).

Parallel Circuit

A circuit configuration where electricity has a choice of multiple paths through which to flow, containing junctions where wires split and join.

Junction

A split or join point in a circuit where a single path divides into multiple branches or multiple branches combine.

Short Circuit

A low-resistance connection that forms an unintended shorter path for current to flow, bypassing other circuit components because electricity follows the path of least resistance.

Variable Resistor (Potentiometer)

An electrical component whose resistance can be adjusted or varied continuously in either direction.

Diode

A semiconductor device that allows electric current to flow through it in only one direction.

Alternating Current (AC)

An electric current that constantly alternates and reverses its direction of flow.

Direct Current (DC)

An electric current that flows continuously in a single, constant direction.

Ammeter

An instrument connected in series (requiring the circuit to be broken so the meter completes it) to measure electrical current in amperes ($\text{A}$) or milliamps ($\text{mA}$).

Voltmeter

An instrument placed across two points in a circuit to measure the potential difference (voltage) between them.

Ohmmeter

A meter setting used to measure the electrical resistance of a component in ohms ($\Omega$) while it is completely disconnected from power.