The phone interviews is initially very conversational. I would say the key to getting this right is to be as extensive as possible in coming up with the solutions for the stated problem and for each solutions, make sure the idea is crystal clear in your mind. One thing that the interviewer always does is to keep asking you questions about something you talk uncertainly. I was asked the usual question about an LED being connected to a 5 V rail and the source is a 120 V AC- how would you make the circuit work. Start with a simple resistor as a solution. Note that the LED has different ways of brightness control and turn-off. So, you can focus on any one of these ( simplest one prefered, both for your sake and the interviewer's ) for your solution. There is also one imaginative question. I was asked the 3 light bulb, 3 switches in a different room question. I was honest and told the interviewer that I had heard about the question earlier. I think that was a good thing as he seemed impressed with my plain honesty. He then asked me- " you are stuck in a trench, deep enough that you cannot get out directly. How would you get out?". You are expected to be really creative, not realistic in this question. So, feel free to make the conversation slightly casual, but keep trying to answer the question all the same. I was able to mention 4 different solutions, some laughable, but accepted. Make sure you mention all the assumptions you make in reaching the solutions. Make sure the interviewer in following your thought process (this applies to all the questions). Also, make sure you understand and convey power electronics concepts on DC-DC and DC-AC-DC conversions very clearly. I was then called for the onsite interview in Coopersberg, PA. This is typically a 5 hour process. Understand this- if your interview gets over after lunch, it does not mean that you are rejected. The process is strictly 5 hour long and they stick to the time schedule. There were 4 rounds of interviews. Make sure you are very attentive when they take you on a tour of the experience center. You HAVE to ask as many questions as possible to the people you meet that day. The fisrt session is a presentation. The second is a tech chat where they ask you the basic light bulb question about which is brighter. They will try to figure out your weak point and question you relentlessly on that. Make sure you do NOT get frustrated or give up at any point. This lasts for an hour and a half usually. Then is the creative question- here the question is more decision making types. This is the tricky part. You are very closely observed on this one. Then the lunch and the office tour. Both are excellent places to ask questions and understand the company and the work culture. But this is a trick part too. I am yet to hear back from them, but their response was fairly good about my performance from their feedback on the interview day and follow-up.