Alternating Current (AC) is an electrical current that reverses direction periodically, unlike Direct Current (DC) which flows in one direction. This type of current is characterised by its frequency, which is the number of cycles it completes per second, measured in hertz (Hz). In most household and commercial settings, AC is used because it can be easily transformed to higher or lower voltages, facilitating efficient long-distance power transmission.
The invention of AC systems is attributed to the work of Nikola Tesla, who developed the first practical AC motor and transformer in the late 19th century. AC power systems use transformers to adjust voltage levels, which minimises energy loss over long distances—a distinct advantage over DC systems. The standard frequency of AC in most residential areas is either 50 or 60 Hz, depending on geographic location.
AC’s ability to easily convert voltage levels allows for the widespread distribution of electricity across vast electrical grids, powering homes, industries, and businesses. Its characteristics also enable the operation of a variety of electrical devices, from simple household appliances to complex machinery, making it integral to modern life and technology.
