What do you need to know about AC/DC.
In the early days of electrification, Direct Current (DC) – where the power flows in one direction like it does through a water hose – was the standard for delivering electrical power. Nowadays, Alternating Current (AC) – where the power flow is constantly switching direction – is the standard. We switched from DC to AC because AC delivers electrical charge more efficiently over long distances.
Since DC is the only type of current that can be stored in a battery, there needs to be a way of converting the AC from the grid into DC. This is done by a rectifier – which for small devices such as smartphones is generally located in the plug of the charging cable, and for larger devices such as laptops it is located in a box attached to the cable.