This document summarizes the key components used in electrical circuits: - A battery is used as a direct current electricity source of a specific voltage, primarily in small circuits. - A resistor increases circuit resistance to reduce electricity flow. Resistors come in different shapes and sizes. - A capacitor is made of two conductive plates separated by an insulator, which prevents the plates from touching. - An inductor is a coil of wire that stores magnetic energy from current flow until it is released. - A fuse protects circuit components from damage due to excessive current, and each fuse type is designed for a specific current amount.