MacBook – Why does the MacBook Air have five pins on the charger

chargermacbook pro

I just got a MacBook Air and noticed the charger has 5 (i.e., an odd number) pins. Shouldn't there be a pair number, one for positive, one for negative charge?

I thought about it being ground, but the charger does not have a ground plug. (Note: the cord does, nevermind)

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Best Answer

From MagSafe Wikipedia page

Pin 1 - Ground
Pin 2 - V+ @ 16.5 V DC
Pin 3 - Charge control pin
Pin 4 - V+ @ 16.5 V DC
Pin 5 - Ground

  • The inner large pins are V+ (16.5 VDC). Measuring with no load will give 6.86 V DC; the full 16.5 V is provided to the proper load.
  • The outer large pins are ground.
  • The tiny center pin is a charge control pin that assists with changing the LED color, as well as reporting the connected adapter type and serial number to the connected Mac.
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