Computer circuits are pathways made of conductive materials that allow electricity to flow and perform various functions within a computer. These circuits are essential for processing data, as they connect different components like the central processing unit (CPU), memory, and input/output devices. They can be found on printed circuit boards (PCBs), which organize and support the electronic components. The basic building blocks of computer circuits are transistors, which act as switches to control the flow of electricity. By combining many transistors, engineers can create complex circuits that perform calculations, store information, and manage tasks. This intricate network of circuits enables computers to operate efficiently and effectively.