Final answer:
The main circuitry of a computer is found in the CPU (Central Processing Unit), which is often referred to as the brain of the computer.
Step-by-step explanation:
The main circuitry of a computer is found in the CPU (Central Processing Unit).
The CPU is often referred to as the brain of the computer and is responsible for executing instructions, performing calculations, and coordinating the activities of other hardware components.
Some examples of CPUs used in modern computers are Intel Core processors and AMD Ryzen processors.