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A digital system is a type of electronic system used to store, process, and manipulate data represented in the form of digital signals, where a digital signal is a discrete time signal. Digital systems use binary number system to operate. Some common examples of digital systems include digital computers, laptops, smartphones, etc.
This chapter is meant for explaining the major components of a digital system.
Components of a Digital System
A typical digital system consists of the following main components −
- Central Processing Unit (CPU)
- Memory
- Input Devices
- Output Devices
- Logic Gates
- Power Supply
- Communication Channels
Let’s discuss each of these components of a digital system in detail.
Central Processing Unit (CPU)
In a digital system, the central processing unit is the most important component of the system, as it performs all the operations in the system. It is also known as processor.
The CPU is an electronic circuit that consists of two sub-circuits namely, arithmetic and logic unit, and control unit.
The arithmetic logic unit (ALU) is the part of a CPU that performs all the arithmetic and logical operations and executes the instructions to manipulate data. ALU is made up of logic gates and other electronic components. It can perform operations like addition, subtractions, comparison, etc.
The control unit (CU) is another major electronic circuit in the central processing unit that coordinate the operation of all other components of a digital system. It generates clock signals for the synchronization of the system.
Semiconductor Memory
Memory is another major component of a digital system. It is used to store and instructions in the system. In most digital system, semiconductor memory is used to store digital information.
Memory of a digital system can be classified into the following two types −
- Random Access Memory (RAM) − It is a temporary memory used to store data and instruction on which the CPU is currently working. Once the digital system is turned off, its data will be deleted.
- Read Only Memory (ROM) − ROM is also an important component of a digital system. It is a permanent memory used to store those data and instructions that require again and again to perform tasks.
In digital systems, both RAM and ROM are used in the form of ICs made up of semiconductors.
Apart from RAM and ROM, digital systems may also support external memory devices like CD, DVD, Pen Drive, SD card, etc. All these external memories are used for permanent data storage.
Input Devices
Input devices are those electronic components of a digital system used for entering data into the system. Examples of input devices include keyboard, mouse, scanner, sensors, camera, light pen, code readers, etc.
Input devices are designed to accept data in the form of a specific type or format and convert them into digital signals for processing.
For example, a keyboard gets outside instructions in the form of keystrokes and then convert them into digital signals.
Output Devices
Output devices are those components of a digital system that allow users to view the processed data or information. Examples of output devices are monitor, display screens, printers, projectors, speakers, etc.
Output devices are designed to accept digital signals and convert them in a suitable format to make them readable by human.
For example, a monitor takes digital signals and convert them as visuals and display on a screen.
Logic Gates
Logic gates are essential components of any digital system. They are the fundamental building block of the digital system. Logic gates are nothing but electronic circuits that can perform logical operations.
In digital systems, logic gates are used to realize all the information processing and storage systems. The most commonly used logic gates are AND, OR, NOT, NAND, NOR, Ex-OR, and Ex-NOR.
Power Supply
Power supply is the energy bank of the digital system that provides necessary electric power to the components of the system so they can work.
The primary function of the power supply unit of a digital system is to convert the electric power received from an external source into the desired type and voltage level required by the system.
Most digital systems work on 5 V DC supply. Hence, the power supply unit receives 220 V AC from the supply mains and convert it to 5 V DC supply. Also, the power supply unit regulates the fluctuations occurring in the power supply to protect the system from damages.
Communication Channels
In a digital system, the communication channel is also known as bus system. It consists of several different types of buses (conductors) such as data bus, address bus, and control bus. These communication channels allow data transmission between different components of the system.
Conclusion
In conclusion, a digital system consists of several components. Some important components of a typical digital system are described in this chapter. All these components are connected together and allowed to communicate to perform different jobs. In the next chapter, we will learn about different types of “digital logic operations”.
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