MagSafe: Information from Answers.com

MagSafe

The MagSafe power adapter on a MacBook.
Type	Computer power connector
Production history
Manufacturer	Apple Inc.
Produced	2006
Superseded	Apple Power Connector
Specifications
Hot pluggable	Yes
External	Yes
Pins	5
Pin out
Male connector, front view
Pin 1		Neutral
Pin 2		V+ @ 16.5 VDC
Pin 3		Charge control pin
Pin 4		V+ @ 16.5 VDC
Pin 5		Neutral
Grey area indicates magnetic connector

The MagSafe connector is a power connector introduced in conjunction with the MacBook Pro at the Macworld Expo in San Francisco on January 10, 2006. The MagSafe connector is held in place magnetically. As a result, if it is tugged on—for instance, by someone tripping over the cord—it comes out of the socket safely, without damaging it or the computer or potentially pulling the computer off of a table or desk.^[1]. MagSafe is similar to the magnetic power connectors that many deep fryers and Japanese countertop cooking appliances have in order to avoid spilling their dangerously hot contents.^[2]

1 Features
2 Pinout
3 Criticisms and defects
4 See also
5 References
6 External links

Features

Boxed 85W MagSafe for MacBook Pro.

The MagSafe connector pins are designed so that the rectangular connector can be inserted in either orientation. LEDs on both sides show green if the computer batteries are fully charged and amber if they are charging. MagSafe can be found on MacBook Pro, MacBook and MacBook Air notebook computers^[3].

Though the 60 W MacBook and 85 W MacBook Pro MagSafe connectors are identical, Apple recommends using only the adapter provided with the machine. The MacBook Air has a smaller 45 W version of the MagSafe adapter.

Apple's MagSafe Airline Adapter is available for DC hookups on certain airplanes.

Apple owns US patent 7,311,526, "Magnetic connector for electronic device", for this technology.

Pinout

The MagSafe connector pins are palindromic. The first and second pin on each side of the tiny central pin has continuity with its mirror pin.

The inner large pin is V+ @ 16.5 VDC. Measuring with no load will give 6.86 VDC; the full 16.5 V is provided to the proper load.
The outer large pin is neutral
The tiny center pin appears to be charge control pin to change LED color and possibly adapter switch off

The rectangular metal shroud has no electrical function. Its purpose is solely for shielding the electrical pins and acting as a ferrous attractor for the magnets within the laptop's power receptacle.

Criticisms and defects

Apple has not licensed third-party products using MagSafe, however manufacturers have devised a workaround: their MagSafe items use the actual connector from Apple’s AC adapter, grafted onto their own product. Since this uses an actual Apple product, purchased legally, no licensing agreements are needed and the patents are not violated.^[4]

Some users have reported (as of April 16, 2008) problems with the quality of the construction of the MagSafe cords, giving the product low marks on the Apple Store’s website^[5]. Common complaints include plug separating from the cord (fraying), transformer shorting, and pin springs losing elasticity.^[6]

Several methods have been devised to protect the MagSafe from failure, including wrapping the cable with tape or sliding protective plastic around the cable.^{[citation needed]}

In 2008, Apple posted official response acknowledging problems with MagSafe adapters, which include incomplete circuit connection and adapter's white insulation separates from the magnetic end of the MagSafe connector.^[7] Following the release of Knowledge Base article, a class action lawsuit was filed in 2009-05-01 in California Northern District Court's San Jose office, alleging that the MagSafe power adapter is prone to frayed wires and overheating, and as such represents a fire hazard, as well as Apple has not taken action to remedy the defects.^[8]

MagSafe with both frayed wires and melted casing, as alleged in the 2009 class action lawsuit

Unfortunately, due to the magnetism of the MagSafe's socket on the product (as of August 20, 2009, solely the line of MacBooks) metallic particles and debris may be attracted to and adhere on and within the socket, potentially leading to electrical shorts on attachment of the power cable. It may be difficult to remove the foreign material.^{[citation needed]}