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MagSafe

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MagSafe
The MagSafe power adapter on a MacBook.
Type Computer power connector
Production history
Manufacturer Apple Inc.
Produced 2006
Superseded Apple Power Connector
General specifications
Hot pluggable Yes
External Yes
Pins 5
Pinout
Male connector, front view
Pin 1 Ground
Pin 2 V+ @ 16.5 VDC
Pin 3 Charge control pin
Pin 4 V+ @ 16.5 VDC
Pin 5 Ground
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 by Apple Inc. The MagSafe connector is held in place magnetically so that, 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]

Features

Apple MagSafe Connector for 2010 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, and also on Apple LED Cinema Display[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. (Note: The 13" MacBook Pro use the 60 W Charger, while the 15" and 17" use the 85 W)

Since the release of the 2010 MacBook Pro, Apple now ships the 60 W and 85W Chargers with right angled MagSafe cord, Similar to that the MacBook Air and Apple LED Cinema Display uses.

Apple's MagSafe Airline Adapter is available for DC hookups on certain airplanes. It will power the computer but not charge the battery.

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 pins on each side of the tiny central pin have continuity with their mirror pins.

  • 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 ground
  • The tiny center pin appears to be charge control pin to change LED color and possibly adapter switch off [citation needed]

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

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

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.[7]

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.[8] 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.[9] Apple has released a new connector to remedy the defects.[10]

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. However, there are very few reports of this complication. [citation needed]

Prior power systems

Prior to the development of MagSafe, early Apple laptop computers such as the PowerBook series used a more standard shell and socket/pin arrangement as seen on non-Apple laptops.

The iBook series introduced a new plug design similar in appearance to a mini-stereo plug, but with an additional metal ring around plug. The first puck-shaped iBook chargers simply had a silver plug body, but the square white chargers introduced a color-changing illuminated ring that indicated charging status.

Tripping on an iBook cord or yanking the cord out at an angle frequently damages the power socket by breaking the solder pads under the connector, resulting in a laptop that would fail to charge when connected to the cord, or would only charge if the inserted plug were propped up or pushed down at an angle. The spring contacts inside the socket connector could also become bent out of position due to angular pressure on the plug, and result in intermittent charging problems. In such situations the illumated power plug functions in an unusual manner which is undocumented. The earlier puck-shaped iBook chargers would also fail to charge if the socket were damaged, but those chargers could not indicate a problem.

In severe cable stress situations, the outer flange of the plug becomes flared and bent, and the tip of the power plug may break off and become lodged inside the socket.

Due to the design of the early 12" G4 iBooks, replacing the damaged "DC-In Board" typically involved a complex 50-step laptop disassembly process[11], resulting in an expensive labor-intensive repair process.

The development of MagSafe prevented the cable strain problems, and eliminated most power connector damage and repair costs for Apple mobile device owners.

References

  1. ^ Apple Unveils New MacBook With Intel Core 2 Duo Processors
  2. ^ "'Break-away' cord aims to make deep fryers safer". CNN. July 4, 2001. Retrieved May 12, 2010.
  3. ^ Apple - MacBook
  4. ^ Macworld | Mobile Mac | A third-party MagSafe solution?
  5. ^ The Apple Store (U.S.)
  6. ^ ibid.
  7. ^ Third party solution to protect MagSafe adaptors
  8. ^ Some MagSafe adapters being replaced by Apple
  9. ^ Apple sued over reputed fire hazard of MagSafe power adapter
  10. ^ Apple Updates Design of MagSafe Connector for New MacBook Pros
  11. ^ http://www.ifixit.com/Guide/Repair/Installing-iBook-G3-12-Inch-DC-In-Board/134/1
Wikimedia Commons has media related to MagSafe.
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