How does the adapter know what voltage it's to output to the MacBook?. I mean: and 85w adapter, for example, will give 14 to 20 volts depending of which MacBook model it's connected to. I read "Teardown and exploration of Apple's Magsafe connector" and this article mentions that the 1pin wire communicates the adapter wattage to the MacBook, but how can it know what voltage to output to the MacBook?.
That is provided by the AC charger, not the port. The charger voltage is fed into a regulator on the motherboard that establishes the fixed or regulated voltage required for the motherboard. Essentially, the magsafe adapter is merely a connecter, nothing more. Most of the newest models run on 5 volts for the basic source. That is the DC regulated voltage. Although you can use the 85 watt charger on most laptops, you cannot use it the new Macbook because it does not have a magsafe port. Most MacBooks only use a 60 or 65 watt charger.
Thanks for your answer. I meant the Power adapter (sorry I said "magsafe"). Macbooks have an input voltage of roughly 14v, 16v, 18v or 20v that then goes to the regulator you say. My doubt is how the power adapter actually knows which power to output for each model.
rodion15 wrote:
Thanks for your answer. I meant the Power adapter (sorry I said "magsafe"). Macbooks have an input voltage of roughly 14v, 16v, 18v or 20v that then goes to the regulator you say. My doubt is how the power adapter actually knows which power to output for each model.
All MBPs require the same voltage.
Ciao.
Different macbooks require different input voltage. For example, a small MacBook Air needs 15v input A large MacBook Pro 20 volts, I checked it myself using a multimeter using an 85 watt power adaptor.
How does a Magsafe adapter know the voltage to output to a Macbook?
