Monitor

A monitor or a display is an electronic visual display for computers. The monitor comprises the display device, circuitry and an enclosure. The display device in modern monitors is typically a thin film transistor liquid crystal display (TFT-LCD) thin panel, while older monitors use a cathode ray tube (CRT) about as deep as the screen size.
Originally, computer monitors were used for data processing while television receivers were used for entertainment. From the 1980s onwards, computers (and their monitors) have been used for both data processing and entertainment, while televisions have implemented some computer functionality. The common aspect ratio of televisions, and then computer monitors, has also changed from 4:3 to 16:9 (and 16:10).

Central processing Unit (CPU)

A central processing unit (CPU), also referred to as a central processor unit, is the hardware within a computer that carries out the instructions of a computer program by performing the basic arithmetical, logical, and input/output operations of the system. The term has been in use in the computer industry at least since the early 1960s.^[ The form, design, and implementation of CPUs have changed over the course of their history, but their fundamental operation remains much the same.

A computer can have more than one CPU; this is called multiprocessing. Some integrated circuits (ICs) can contain multiple CPUs on a single chip; those ICs are called multi-core processors.

Two typical components of a CPU are the arithmetic logic unit (ALU), which performs arithmetic and logical operations, and the control unit (CU), which extracts instructions from memory and decodes and executes them, calling on the ALU when necessary.

Not all computational systems rely on a central processing unit. An array processor or vector processor has multiple parallel computing elements, with no one unit considered the "center". In the distributed computing model, problems are solved by a distributed interconnected set of processors.

The abbreviation CPU is sometimes used incorrectly by people who are not computer specialists to refer to the cased main part of a desktop computer containing the motherboard, processor, disk drives, etc not the display monitor or keyboard.

Webcam

A webcam is a video camera that feeds its image in real time to a computer or computer network. Unlike an IP camera (which uses a direct connection using ethernet or Wi-Fi), a webcam is generally connected by a USB cable, FireWire cable, or similar cable.
Their most popular use is the establishment of video links, permitting computers to act as videophones or videoconference stations. The common use as a video camera for the World Wide Web gave the webcam its name. Other popular uses include security surveillance, computer vision, video broadcasting, and for recording social videos.
Webcams are known for their low manufacturing cost and flexibility, making them the lowest cost form of videotelephony. They have also become a source of security and privacy issues, as some built-in webcams can be remotely activated via spyware.

webcam

Speaker

Computer speakers, or multimedia speakers, are speakers external to a computer, that disable the lower fidelity built-in speaker. They often have a low-power internal amplifier. The standard audio connection is a 3.5 mm (approximately 1/8 inch) stereo phone connector often color-coded lime green (following the PC 99 standard) for computer sound cards. A few use an RCA connector for input. There are also USB speakers which are powered from the 5 volts at 500 milliamps provided by the USB port, allowing about 2.5 watts of output power. 

               Computer speakers range widely in quality and in price. The computer speakers typically packaged with computer systems are small, plastic, and have mediocre sound quality. Some computer speakers have equalization features such as bass and treble controls.
The internal amplifiers require an external power source, usually an AC adapter. More sophisticated computer speakers can have a subwoofer unit, to enhance bass output, and these units usually include the power amplifiers both for the bass speaker, and the small satellite speakers.
Some computer displays have rather basic speakers built-in. Laptops come with integrated speakers. Restricted space available in laptops means these speakers usually produce low-quality sound.

Printer

External device that communicates with another digital device to print what a user sees on a screen. Printers use small pixels to transfer an image from the system to another surface. Ink jet and laser printers are the most commonly used varieties of this device, and are most commonly hooked up to a personal computer. Some printers only print in black and white, but most include a  colour option as well.

inkjet printer

laser printer

Optical mouse

A mouse is a small plastic box with buttons on top and a rolling ball or optical 'reader' underneath. A mouse is a pointing device that is another form of input device that enables the user to freely move an on-screen pointer and to select text, menu options, icons, and other on-screen objects.

wired optical mouse

wireless optical mouse

Hardware

Hardware is a component that allows users to enter
 data and instructions into a computer.There are two
 types of hardware such as input and output.
Input is any data and instructions entered into the
memory of a computer.




1 : TEXTS - input from keyboard and barcode reader.

Keyboard - input device that contains keys users press to enter data and instruction into a computer. We can enter data such as text and commands into a computer by pressing the keys on the keyboard.

Introduction

Computer is an electronic device, operating under the control of that can accept data (input) , process the data according to specified rules (process), produces result (output) and store the results for future use (storage). The input service is any hardware component that allows users to enter data and instructions into a computer. The input is any data and instructions entered into the memory of a computer.