How does a macbook power adapter know the voltage to output to a Macbook?

[rodion15]

How does the power 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?.

 

[learninmypc]

I googled your question & oddly enough your paragraph is exactly( or close enough to) the same as http://www.tomsguide.com/answers/id-2705860/macbook-power-adapter-voltage-output-macbook.html

 

[mailpup]

Good catch. Not so odd since the OP used the same username in that other forum.

 

[learninmypc]

Lol, I didn't notice the same username.