AC & DC

Alternating current (AC) is an electric current which periodically reverses direction and changes its magnitude continuously with time in contrast to direct current (DC), which flows only in one direction.

AC = Alternating current
DC = Direct Current 

In short, AC is the power that is in everyone's homes and businesses as their primary electricity supply type. Drivers for LED lights consume this power and convert alternating current (AC) to direct current (DC). This ensures the power supply is constant, and uninterrupted and through clever design - prevents overheating, flickering, colour changes and degraded performance.