High tech industry

I’d like to go into companies that develop hi-thech products such as Samsung or Sony. Does that mean I have to know significant knowledge of electronic engineering? I certanily do use many products that are high tech, but I’m still uncertain how all the inner workings are put together.

Is there need to choose specific area where I want to work when I am applying for these companies such like cellphone or computer department? Not that I want to limit myself to a certain task, but people are always telling me be clear about my goals.