The main circuit board of the system unit is called a motherboard. It is also known as the main circuit board, system board or logic board in Apple computers. It is the foundation of all of the computer's vital functions.
The motherboard allocates power to the Central Processing Unit, the Random Access Memory and all of the computer's hardware. The jumpers found in the motherboard close electrical circuits to configure components like hard drives, modems and sound cards. It allows these components to communicate with one another. The motherboard also contains connections to allow external connections, such as USB headers.