Charge, an inherent property of matter, is responsible for a wide range of electric phenomena. The SI unit of charge is the coulomb. All matter comprises atoms, which consist of three subatomic particles: protons, neutrons, and electrons. When the number of protons and electrons are the same, the atom is electrically neutral. Charges can be transferred from one body to another, and the net charge within the system remains the same. Charges are quantized, meaning the charge on a body is always the integral multiple of the electronic charge. When a conducting wire is connected to a battery, the movement of charges within the wire creates current. Current is the time rate of flow of electric charge, measured in amperes. Conventionally, its direction is considered opposite to the flow of negative charges. The charge transferred over a specific time interval can be obtained by integrating the current with respect to time. There are two most common types of currents. A direct current remains constant with time, while the alternating current varies sinusoidally with time.