Components of computer
Control unit in cpu
Input devices
Keyboard
- Wireless keyboard use Bluetooth that can be kept at a distance from the monitor so that it does not affect our eyes.
- It works on creating a new coordinates on the surface on which it is kept. It divides the surface into X and y coordinates ,the old mouse contained a heavy ball that starts rolling when the mouse is moved and from a new co-ordinate but the optical mouse contains a very small lightning device and a very small camera that can take multiple images of the surface on which it is is kept.
- It does not depend upon friction there for it is more durable.
- It can read the data in optical form for example barcode reader, QR code reader, holostore, scanner.
- The scanner reads the data through optical form where intensity of light is used to create the digital code of 0 and 1.
- When this data is sent to printer it forms electrical pulses.
- It works on the principle of hologram technique, in hologram 2 images are created at the same point to create an illusion of a 3D image. In a hollow store the optical images are used to create a 3D image ,it is computer data storage device that gives its output in optical form.
- Ports are the carriers of data and charges. Some of the important types of ports are
- RJ-45 Ethernet: It is used to connect devices in Ethernet.
- SATA: it is a fast charger and a data carrier that can provide high speed up to 10 gbps but it uses a separate data port for charge and separate for data carrier.
- Thunderbolt :for the first time it was launched by Apple computers for their Mac and iPhone devices. It is also a fast data carrier and fast charger that can provide speed up to 10 gbps. It is a single data port and charge port both to carry data and charge at the same time. It allows a two way transfer of data therefore it is called as a bi-directional bus.
Cache memory
- It is a faster than RAM and ROM but it is slower than registers.
- It stores the frequently used data in the form of cache file and it can deliver this data next time when it is asked. Therefore cache memory works faster but it is costlier also.
- It is the fastest memory that stores vital instruction of computer in the form of a register file.
- It is a permanent memory.
Output devices
Printer
Impact printer
- There is a contact between paper and printing head in this, the impact printer are of three types.
- It is based on typewriter technology in which printing takes place using pressure there for inkblots and the image quality becomes poor.
- Only one characters can be printed at a time therefore the printing is very slow.
- It cannot print non alphanumeric characters example #,$.etc ,also printing cost is very high in it.
- These printer have an inked ribbon between the paper and the printing head.
- In place of printing head it uses small pins.
- These pens strike on paper to create images in the form of matrix of dots.
- The dot matrix printer has less cost of printing and it can print non alphanumeric character also.
- These printers have less printing cost.
- It uses specialised paper with chemical layer on it ,this chemical layer is bond using heated pens that strike on the paper to create images in the form of matrix of dots.
- It is used in ATM
Inkjet printer
- It gives best quality of image in colour.
- Inkjet printer uses electrostatic forces to guide Ink to create images in the form of matrix of dots.
- It is also based on same principle as that of inkjet printer but it used solid ink in place of liquid ink and also the solid ink is dried using laser light.
- Therefore it saves times and increases speed of printing.
- It is also based on the same principle as that of inkjet printer and laser printer but it uses die in place of ink.
- The solid die is guided under electrostatic forces strikes on chemical glossed papers and converts directly into gas.
- Therefore called as a sublimation printer.
- It is used for printing on t shirt ,flex printing, quick photograph , etc.
- The dye sublimation printer can create images like a photograph.
- It is used to print continuous lines in ECG machines ,sismographe ,etc.
- It is used by architect ,town planners ,medical professionals ,etc ,a plotter consists of a very thin pen to draw continuous line while a printer uses discontinuous dot matrix to print.
LCD (liquid crystal display)
- The LCD screen uses crystals made up of plasma material.
- When it was heated radiation come out of it and falls on the grid pattern screen to create images.
- It was an improved version then plasma screen because plasma monitors at the problem of screen burn.
- Screen burn appears when there is a static image on screen for a longer time. To remove this problem is screensavers are used.
- Screensaver is a randomly moving image that can create uniform heating and cooling.
- In it the two screen are integrated together so that the image appear nearer brighter and better.
- Touchscreens become highly popular in mobile devices.
- It is a type of LCD screen in which the crystal are of variable intensity due to which the images formed were of better colour.
- These are made up of gallium arsenide phosphide material
- These diode can be made into a very small size , therefore it gives high pixel density.
- Hence it can support high definition or ultra HD images.
- Diodes consume much less electricity seems its heat output is very less also these diodes do not have much glaring effect.
QLED - quantum dot LED
- It is also called as real life like images screen.
- It is made up of diodes of very small size called as quantum dots.
- These diodes are of so small size that it forms images comparable to the images formed by our eyes because the pixel density of such images are same.
- Therefore the quantum dots LED can form image that looks real.
- It does not use backlight hence it has no glaring effect.
- In OLED the diodes are made up of hydrocarbon chain.
- These hydrocarbon Chain are printed on a conducting surface when current is passed through such surface the hydrocarbon chain starts growing creating images such images are called true colour images.
- Even the black images called as a true black image.
- It does not use backlight hence it does not have any glaring effect such scenes are very thin therefore it is foldable and reliable.
PMOLED - passive matrix OLED
- It has no concept of backlight therefore black colour images are not visible when the external light is not sufficient therefore such a screen can only be used during the availability of sufficient light example kindle tab .
- It is also a type of solid in which there is a concept of backlight also due to which the screen image is visible in sufficient light and insufficient light both example galaxy note 8, iPhone 10.
- The touch panel and screen both are integrated together so that the screen becomes thinner and image quality becomes better.
Resistive touch
- It consists of two screen top screen is only a protective layer and the bottom screen is a highly sensitive pressure reactive screen.
- When pressure is applied on the top screen it migrates to the bottom screen and the command related to given point is obtained ,such screens are not instant reactive screen because the transfer of pressure takes time, due to two screens image quality is poor.
- Sometime pressure transfer does not takes place hence response not obtained.
- Due to application of pressure every time the screen gets damaged easily.
- It consists of a single screen with the touch panel.
- The screen is charged when it is lost charge transfer takes place and the response is obtained.
- Since there is no gap between the touch and the charge transfer.
- Such screens are called as instant reaction screen.
- Due to single screen the image quality is very good in it.
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