An AC adapter switch usually refers to an AC adapter designed specifically for the Nintendo Switch console. More generally, an AC adapter is an external power supply that converts AC (alternating current) from a wall outlet to the proper DC (direct current) voltage required by electronic devices. For the Nintendo Switch, the AC adapter provides power and charges the battery through a USB Type-C connector. It can be used to power the console even while playing. The adapter converts mains voltage to a safe and suitable DC voltage for the Switch. This kind of adapter is sometimes called a "power brick" or "wall charger." More technically, many modern AC adapters (including those for the Switch) are switched-mode power supplies (SMPS) that efficiently convert electricity by switching on and off rapidly to transform and regulate voltage. This design is compact and lightweight compared to older linear power supplies. In summary, an AC adapter switch refers to the power adapter for the Nintendo Switch, which:

• Converts household AC voltage to safe DC voltage
• Connects via USB-C to the Switch console
• Supports powering and charging while gaming
• Typically uses switched-mode power supply technology for efficiency and compactness

This is distinct from a generic "power switch." The term "AC adapter switch" in your query likely points to the Nintendo Switch AC adapter power supply unit. If you meant something else by "AC adapter switch," please clarify. But for the Nintendo Switch context, it is the power supply charger that plugs into the console and the wall outlet.