What are the components of the CPU?

CPU stands for Central Processing Unit. It is the soul of a computer system. The CPU along with the memory and the I/O sub-systems establish a strong computer system.

A CPU includes small layers of hundreds of transistors. Transistors are microscopic bits of substances that block electricity at one voltage (non-conductor) and enable electricity to move through them at multiple voltages (conductor).

These slight bits of substantial are the semiconductors that create two electronic inputs and create multiple outputs when one or both inputs are turned on.

CPU is the most significant in a computer system. It is the component that regulates all internal and external devices and implements arithmetic and logic operations to perform the set of instructions saved in the computer’s memory.

Components of CPU

A CPU includes three major components that are as follows −

Register Set

The register set contrasts from one system to another. The register set includes several registers which contain general-purpose registers and special-purpose registers. The general-purpose registers do not implement any particular function. They save the temporary information that is needed by a program. The special-purpose registers execute various functions for the CPU.


The ALU implements all the arithmetic, logical, and shift operations by supporting important circuitry that provides these evaluations.

Control Unit

The control unit fetches the instructions from the main memory, decodes the instructions, and then executes them.

The CPU interacts with the main memory and input/output devices. The CPU reads and writes data to and from the memory system and transfers data to and from the I/O devices.

An elementary execution cycle in the CPU can be defined as follows −

  • The CPU fetches the instruction to be implemented from the main memory and saves it in the Instruction Register (IR).
  • The instruction is decoded.
  • The operands are fetched from the memory system and stored in the CPU registers.
  • The instructions are then executed.
  • The results are transferred from the CPU registers to the memory system.

If there are more instructions to be executed, the execution cycle repeats. Some pending interrupts are also tested during the execution cycle.

Example − The interrupts including I/O device request, arithmetic overflow, or pages are tested during the execution cycle.

The procedures of the CPU are represented by the micro-orders issued by the control unit. The micro-orders are the control signals, which are transfer over-determined control lines.

CPU is the main component of a computer system. It can give out each instruction of a program to implement primary arithmetical, logical, and input/output operations.

Updated on: 14-Sep-2023

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