I've interviewed on two separate occasions for hardware positions with Apple. Most (but not all) of the interviewers are nice enough.

First interview had circuit design questions; the second did not. Both interviews were divided into several one-on-one sessions, 30 minutes each.

If you're not selected (which I wasn't), they just leave you hanging. At first, I thought it was just a lazy recruiter, but the second time it happened, I realized that it must be a policy to not contact you or respond in any way if you are not chosen.

This is not a way to leave a good impression. After wasting time with them on the phone multiple times and taking time off to interview in person, I don't think it is too much to ask for a form email to let you know you weren't selected (if their competitors can do it, I think Apple can as well).

I doubt I will bother to interview with them again.

Design an LED driver using an op-amp.