Glossary · Kits and equipment

AC vs DC: Alternating and Direct Current, Explained Simply

AC and DCAlternating current and direct current

Direct current (DC) flows one way, as from a battery or a solar panel. Alternating current (AC) switches direction 60 times a second and comes from outlets.

  1. Panel or batteryDirect current: one direction, steady voltage.DC
  2. InverterSwitches it back and forth 60 times a second.AC
  3. Outlets and the gridAlternating current, what US homes run on.
In a plug-in kit or a power station, the panels and the battery are DC; the inverter makes the AC that your outlets and appliances expect.

At a glance

DC
Flows one way: batteries, solar cells, LEDs, computers, EVs
AC
Reverses direction 60 times a second in the US
The grid
Runs on AC; voltage changes easily with a transformer
Converter
An inverter turns DC into AC

Direct current runs continually in one direction, as from a battery or a fuel cell. Alternating current reverses direction a certain number of times a second, 60 in the US, and can be converted to different voltages easily with a transformer, which is why the grid uses it. Both definitions are the Department of Energy’s, from its history of AC and DC.

Why does it matter for solar and batteries?

Solar cells, batteries, LEDs and computers all run on DC, the DOE notes, but your outlets supply AC. So anything that connects solar or a battery to household power needs an inverter: the microinverter in a plug-in kit, or the one built into a portable power station.

How do I tell which one a device uses?

Look at the label or the charger: an adapter’s label lists its input (AC from the wall) and its output (usually DC for the device). On a power station, the regular outlets are AC; the USB and car-style ports are DC.

Published by the Plugged Sun editorial team

Sources

  1. The War of the Currents: AC vs. DC Power (Official document, US Department of Energy, 2014)
  2. Solar Integration: Inverters and Grid Services Basics (Official document, US Department of Energy, 2026)

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