A 12V 1A AC adapter is a power supply that converts alternating current (AC) from a wall outlet to 12 volts of direct current (DC) with a maximum current output of 1 ampere. It is commonly used to power various low-power electronic devices that require a 12V DC input, such as routers, modems, LED lighting, and CCTV cameras. The adapter ensures a stable and regulated 12V DC output, protecting devices from overvoltage or overcurrent.