What are all in a desktop computer

Components of a computer

What are the components of a desktop PC? On this page you will find a brief explanation of the individual components.

Desktop PCs are becoming less important in private households

In the age of smartphones, tablets and ultrabooks, you can hardly see the inner workings of the hardware. Desktop PCs are becoming increasingly rare in households, and the idea of ​​tinkering with them yourself seems downright anachronistic today. If you still want to understand how a computer works, whether on your desk or in your pocket, the classic desktop PC is best suited to determine the individual components and their functions.

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Processor (Central Processing Unit / CPU)

This is the central processor in which all program commands are interpreted and executed and the processes are coordinated. It is largely responsible for the computing speed. This is measured in MHz (megahertz) or GHz (gigahertz).

RAM (Random Access Memory / RAM)

This is the computer's main memory and working memory, measured in MB (megabytes). The data with which the computer is currently working is managed here. It is always advisable to upgrade the main memory, as the computer speed depends heavily on the size of the available RAM memory. If there is not enough physical RAM available, the computer tries to add "virtual memory" from the hard disk. However, since the hard disk can be accessed much more slowly than the fast RAM, problems arise with video or audio editing programs. Work processes slow down, there are “jerks” and the like.

Motherboard with bus systems and interfaces

The motherboard combines the CPU, RAM and the slots for the expansion cards for graphics, sound, modem and so on. The bus systems are used to transfer data between the various computer components. The processor is supplied with data and program commands from the main memory via conductor tracks on the motherboard. The speed of the computer also depends on the performance of the bus systems.

Internal interfaces and slots ensure data transfer to the expansion cards and drives. The PCI bus (Peripheral Component Interconnect) has established itself as the internal interface for PCs: expansion cards such as graphics and sound cards are integrated into it.

Serial ATA connector

AGP (Accelerated Graphics Port) was introduced as an additional slot, which can transmit larger data streams and is therefore also suitable for faster graphics cards. In the meantime, PCI-Express (PCIe) with very high data transfer rates has appeared in order to replace both AGP and PCI. The Serial ATA interface is used today to connect internal hard drives. Until recently, the parallel ATA (or IDE, EIDE) interface was still common.

hard disk

The hard drive is the main memory for all data that should be retained even when the computer is switched off. The size of hard drives is specified in gigabytes (GB). They consist of one or more rotating plates that move at speeds of 5,400 to 15,000 revolutions per minute. External hard drives are integrated via a USB or Firewire interface.

graphic card

The graphics card is used to display the image on the monitor and the possible image and color resolution depends on it. All graphics cards available today meet the common requirements, only computer games have higher demands. The realistic representation of artificial worlds using 3D techniques has led to rapid development in this area. Special GPUs (Graphic Processing Units) take over the graphics calculation and fast memories increase the processing speed.

If videos from camcorders (video digitization card) are to be played on the computer or television images (TV tuner card) are to be received from the cable network, the graphics card must have inputs and outputs to which the camera and video recorder or the antenna cable can be connected can.

Sound card

A sound card is part of the standard equipment of a computer, which enables it to record and play back speech and music. In many cases, sound functions are also integrated into the motherboard (onboard), which are quite sufficient if there are no special demands on the sound quality. This depends on the bit rate (16 bit corresponds to HiFi quality) and the sampling frequency (a CD has a sampling frequency of 41 KHz).

Various inputs and outputs are possible for connection to hi-fi systems, microphones and loudspeakers. There are analog connections for jack plugs, cinch sockets or midi plugs and digital connections such as SDIF.

CD-ROM / DVD drives

CD and DVD use optical storage methods. In contrast to a CD, a DVD can be written on both sides; it also has a higher data density and two parallel data layers. A CD offers 700 megabytes of storage space and a DVD from 4.7 to 17 gigabytes, depending on the type.

There are write-once blank discs (CD-R and DVD-R / DVD + R) and rewritable discs (CD-RW and DVD-RW / DVD + RW).

There are two competing systems for DVDs, known as the plus and minus standards, and they are not compatible with each other, so that when buying a blank disc you have to pay attention to the respective standard of the burner.

Input and output devices

Monitor, mouse and keyboard are the classic interfaces with which humans make contact with the computer. Printer, scanner, modem, webcam, loudspeaker or joystick are also common input or output devices. In addition, there are so-called graphic pads, up to A3-sized plates, on which you can draw and write with a pen. These are mainly used by graphic designers. Voice input and output devices, glasses that enable a three-dimensional view and data gloves equipped with sensors that translate finger movements as mouse movements in the computer have already been partially implemented. The games and entertainment industry in particular is investing in new developments.

General links

Wikipedia: Hardware category

The free encyclopedia Wikipedia offers a lot of introductory, but also detailed information about computer hardware.

To the website


The electronics compendium contains many details on computer technology.

To the website

Teaching media at SESAM

At SESAM you will find teaching materials and media on everything to do with computers.


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