Apple MagSafe Power Adapter

Apple MagSafe Power Adapters are power supplies introduced in 2006 by Apple for use with MacBook models with MagSafe ports. The adapters are available in various wattages, to support different power requirements of devices.

Overview
The MagSafe Power Adapter features extendable cord holders, and a magnetic DC connector that can safely disengage to reduce the risk of damage when the cord is accidentally tripped over. The magnetic connector is available in "T" or "L" (also called "barrel") shape styles.

When the magnetic connector is securely attached, the delivery of a current is indicated by a small LED light at the head of the connector. The LED light will appear in an amber color to indicate that the device is charging, while a green color will indicate that the battery has been fully charged. The electrical transformer is enclosed in a white polycarbonate block with a removable AC "duckhead" connector that can be swapped for a Power Adapter Extension Cable. It can continue to supply power to a device in which the battery is depleted or missing, though this may lead to CPU to prevent spontaneous shutdowns caused by the device drawing more current than available.

Supported Macs
MagSafe Power Adapters are interchangeable as long as the adapter can supply the minimum wattage required by the device. Attaching a low-wattage adapter to a high-wattage device can electrically overload the adapter, causing it to fail or for throttling to be activated.
 * MacBook (2006 to mid 2010, original non-Retina) — requires 60W or greater
 * MacBook Air (2008 to 2011) — requires 45W or greater
 * MacBook Pro 13" (2009 to mid 2012) — requires 60W or greater
 * MacBook Pro 15" (2006 to mid 2012) — requires at least 85W
 * MacBook Pro 17" (2006 to mid 2012) — requires at least 85W

Older MagSafe Power Adapters can be used with newer devices with MagSafe 2 ports by using a MagSafe to MagSafe 2 Converter.