Electricity

A complete set of vocabulary and key concepts for GCSE Electricity Paper 1, including circuit symbols, component characteristics, formulas, and circuit rules.

Voltmeter

An instrument used to measure potential difference (p.d.).

Potential difference (p.d.)

Defined as the "work done per unit charge," calculated using the formula $V = \frac{E}{Q}$, where $E$ is energy transferred.

Ammeter

An instrument used to measure current.

Current

The "rate of flow of charge" per second, calculated using the formula $Q = I \times t$.

Resistance ($R$)

A measure of the opposition to the flow of current. A higher resistance means a greater opposition ($R \uparrow I \downarrow$).

Ohm's Law

States that potential difference is directly proportional to current flowing ($V \propto I$) at a constant temperature.

Diode

A component that allows current to flow in only one direction and has very high resistance in the other direction.

Thermistor

A temperature-dependent resistor where resistance decreases as temperature increases ($\text{Temp} \uparrow \text{Resistance} \downarrow$); used in thermostats.

L.D.R. (Light-Dependent Resistor)

A component where resistance decreases as light intensity increases ($\text{Light} \uparrow \text{Resistance} \downarrow$); used in street lights.

Filament lamp resistance

As p.d. increases, temperature increases, which causes resistance to increase due to the vibration of ions, currents stops increasing

Series circuit

A circuit with only one path for electrons, where current is the same at any point and p.d. is shared between components.

Parallel circuit

A circuit with multiple paths for electrons, where current is shared between paths and p.d. is the same across each path.

Resistance in Series

The total resistance is found by adding the individual resistances together.

Resistance in Parallel

The total resistance is lower than the value of the lowest individual resistor.

L.E.D. (Light-Emitting Diode)

A specific type of diode that emits light when current passes through it in the correct direction.

Battery

An electrical component formed by connecting two or more cells together.