Electrical Engineering is usually divided into many specialties –  Power, Control, Microelectronics, Signal processing, Telecommunications, etc. and it’s rare for engineers to move away from their specialty. I’ve found that Embedded Engineers are sometimes required to work in many of these areas at once – to be able to get an application off the ground, you need to be able to understand many of the issues surrounding the system. Imagine how a microcontroller would perform if its supply rails were full of noise due to a bad power supply design or trying to perform an FFT on an 8-bit microcontroller? This clearly calls for knowledge in many disciplines.