I applied for the hardware internship through Apple's website. There were three interviews that lasted about four weeks.
I did not get into the fourth interview.
The working principle of an ADC.
The working principle of a buck converter.
MOSFETs.
The following metrics were computed from 126 interview experiences for the Apple Hardware Engineer role in United States.
Apple's interview process for their Hardware Engineer roles in the United States is very selective, failing most engineers who go through it.
Candidates reported having very good feelings for Apple's Hardware Engineer interview process in United States.