Direct Current (DC)

Direct current (DC) is a one-directional flow of electric charge through a conductor. Unlike alternating current (AC), which periodically reverses direction, DC flows at a constant polarity. Batteries, solar cells, and USB power supplies all produce DC. Electronic circuits — including the processors, memory, and peripherals inside computers — run on DC power, which is why devices that plug into an AC wall outlet contain power supplies that convert AC to DC internally.

In This Home

The lab servers and networking gear all run on DC internally, even though they are powered from AC wall outlets. The [APC UPS](50-Devices/Home Network/APC UPS.md) stores energy as DC in its batteries and inverts it back to AC to power connected equipment during an outage.