JK-TK/GRADE-8-TERM-2 huggingface dataset:
Data bus 3. Control bus The buses connect the CPU microprocessor to each of the memory and I O devices. The CPU is involved in sending or receiving information to or from memory location, input or output device, and a secondary memory device FDD or HDD . When the CPU sends data to a device or memory, it is called WRITE operation and when the CPU receives data it is called READ operation. The functions of buses are described now. Address Bus The address bus is unidirectional, information flows over it only in one direction, from the CPU to the memory or I O devices. The CPU generates addresses on the lines of the address bus. Each of the addresses corresponds to one memory location or one I O device. When the CPU wants to communicate with READ or WRITE , a certain memory location or I O device, it places the appropriate address on its address output. This address is then decoded to select the desired memory location or I O device. This decoding process usually requires address decoder circuits. Microprocessor local buses Data Bus The data bus is bidirectional and data can flow to the CPU through it. The data bus can be either input or output depending on whether the CPU performs a READ or a WRITE operation. During READ operation the data bus receives data that has been placed on the data bus by memory or I O device selected by the address. During WRITE operation the data bus acts as the output and places data on the data bus which are sent to a selected memory location or I O device. Control Bus The control bus consists of a set of signals that are used to synchronize the activities of separate microcomputer elements. Some of these control signals are sent by the CPU to the other components to tell them the type of operation in progress. The I O devices can send control signals to the CPU. Read Write, Rest, and interrupt are examples of control signals used in a microcomputer. Other busesCOMPUTER MONITOR OR VIDEO DISPLAY UNIT TYPES, AND FEATURES VDU 1. Short for visual display unit, VDU is an any device used with computers to display text and images. For example, a flat-panel display and a projector are both examples of VDUs. However, VDU most commonly describes the CRT cathode ray tube monitor, a now archaic standard replaced by flat-panel display methods like LED lightemitting diode . Early VDUs had a 13" screen size.
For example, a flat-panel display and a projector are both examples of VDUs. However, VDU most commonly describes the CRT cathode ray tube monitor, a now archaic standard replaced by flat-panel display methods like LED lightemitting diode . Early VDUs had a 13" screen size. By the mid-1990s, 15" and 17" VDU screen sizes became more common, with some 20" screen sizes being released. By the early 2000s, flat-panel monitors with 15" and 17" screen sizes gained popularity and started replacing CRT monitors. 2. Short for video display unit, VDU is a computing device that allows input from a user and output to a display, like a computer monitor. A VDU consists of a display device and a keyboard and could include a mouse. In the United States, it is sometimes known as a video display terminal or VDT video display terminal . Please note The computer monitor is an output device that is used to display softcopy data that is processed on the system unit. A computer monitor is also known as a screen or Visual Display Unit VDU . Some types of computer monitors are CRT, LCD, TFT, Plasma, OLED, LED, touch screen, and curved screens. To acquire a new computer screen, some of the features to consider are resolution, size, technology, refresh rate, video connector, aspect ratio, and viewing angle among other factors. Types of Computer monitors Computer monitors have evolved from the bulky big Cathode Ray Tube monitor to the ultra-slim curved screen that we have today. Some of the computer monitor types that you will find in the market include: 1. Cathode Ray Tube CRT . These are the oldest types of computer monitors and they used the technology of cathode rays. On the back of the screen, there is a cathode gun that shot rays through a vacuum into the screen. The screen has an anode and material that glows when hit by the electrons. The rays hit the glowing material and the image is created appropriately. The monitor had a long back side because the front and cathode gun had to be at a distance for it to give the best results. 2. Liquid Crystal Display LCD . They used the crystal liquid which is easy to be manipulated and changed when light strikes it. Compared to CRT they are lightweight, slimmer, and use less power. 3.
They used the crystal liquid which is easy to be manipulated and changed when light strikes it. Compared to CRT they are lightweight, slimmer, and use less power. 3. Light emitting diode LED It uses the light-emitting diode as the backlight which makes it slim because it doesn t need the distance that is required in CRT. They produce images with high resolution, are slimmer, less bulky, and produce less heat and less power. 4. Organic Light Emitting Diode OLED It is the latest technology an improvement from LED but still very expensive to produce in bulky. It has an organic substrate that glows when electricity is passed through it. They use less power and they are even slimmer because they don t need backlight since the substrate can produce light. 5. Touchscreens monitors Currently, computer screens are manufactured to take instruction from the human touch. An operating system such as Microsoft Windows 8 and above versions was developed to support a touch screen operation. There are 4 main technologies used for touch screens. A. Capacitive touch screen These screens use the capacitor concept which stores charge. Since the human body has electrical charges when you touch the screen at a specific position you discharge that particular point. The information is then sent to the processor which interprets what needs to be done. They are mostly used on smartphones in today s applications. B. Resistive touch screen The resistive screen uses the concept of resistors where it has two layers with a gap between them. For it to be effective the user has to press and not just touch because the two layers must make contact at the point where it has been pressed. When it is pressed the point can be identified and interpreted appropriately. These touch screens can be touched with a finger and any other objectthat can exact pressure and not a must that it has electrical changes. C. Infrared touch monitors They have an infrared emitter and receiver which create an invisible grid of rays. When you touch the screen you disrupt the ray transmission which is then recorded as a touch. D. Surface acoustic wave monitor These touch screens use sound waves to detect the touch. They have transducers and receivers on the opposite corners of the screen. When you touch the screen you disrupt the sound wave which is sensed as a touch command. 6. Plasma display panel They are flat-panel types of screens made up of small cells containing plasma. Plasma contains charged particles ions and electrons .
6. Plasma display panel They are flat-panel types of screens made up of small cells containing plasma. Plasma contains charged particles ions and electrons . When electricity is passed through them they emit light which forms an image. They are not common computer screens because they are more economical for big-size screens. 7. Curved computer monitor These are replacing flat screen monitors by offering a curved viewing screen. They offer a better viewing angle compared to a flat screen Factors to consider when choosing a good computer monitor1. Resolution: It is the number of pixels that can be displayed per inch of the screen. The higher the number the more clear the image that is displayed. 3. Aspect ratio: It is the ratio of the length horizontal and width vertical of the monitor. It determines how the image will be stretched on the screen. The main ratios are 4:3 and 16:10. 4. Viewing angle: It is the angle where you can view the image without distortion. CRT screens had a wide viewing angle than LCD screens. 5. Power consumption: LCD uses the least power compared to CRT and OLED type of technology. Less power means power is conserved and also it reduces overheating. 6. Technology: screen comes from different technology modes as discussed in different types above. The technology will determine the image quality, cost, and user preference. 7. Connector video input: latest video connector for monitors is HDMI. However, to be on the safe side you should have a computer screen that supports more than one way of connecting. If you are buying a screen for an already existing system unit make sure you check which is a compatible type of supported connection. 8. Ergonomics: most users spend more time on the screen and would like to get a screen design for comfort. Select a screen that has height adjustability, and can change screen brightness and contrast among other designs. 9. Refresh rate: this is the rate at which the screen can refresh the displayed image per second. A higher refresh rate means the image will be clear and it will not look like it hangs. It is measured in hertz and the higher the better. Most computer screens have 144Hz. 10. Contrast and brightness: contrast ratio is how dark the black part is and how bright the white parts of an image can get. While brightness is the measure of light that the screen can produce. 11. Built-in speakers: latest monitor come with an inbuilt speaker that can be used to complement the system unit speakers.
While brightness is the measure of light that the screen can produce. 11. Built-in speakers: latest monitor come with an inbuilt speaker that can be used to complement the system unit speakers. 12. USB port: USB port is a common connector interface in today s devices including screens. They can be used to load data without even connecting to the system unit. For future improvement and use, you can select a monitor that has a USB port. Types of computer screen connectors Every computer offers a connection port that allows the computer monitor to be connected to the system unit so that it can receive data being transmitted. Most monitors are connected using a VGA cable. The cable connects the VGA card which translates the information from the system unit into images and text that the user can be able to view. Other screen connectors are AUX, HDMI, DVI, and Display Port. Structure of Visual Display Unit The structure of a Visual Display Unit VDU can vary depending on the specific type of device, but most VDUs have several key components in common. Here is a general overview of the structure of a VDU:1. Display panel: This is the part of the VDU that actually displays the visual information. It is typically made of a thin layer of crystal or plastic, and can display images using a variety of technologies, such as liquid crystal display LCD or organic light-emitting diode OLED . 2. Backlight: Many VDUs, especially those used in portable devices, use a backlight to illuminate the display panel. This helps to make the images on the screen more visible in low light conditions. 3. Circuitry: The VDU contains a number of electronic circuits that control the display panel, the backlight, and other components of the device. 4. Housing: The VDU is typically enclosed in a housing or casing that protects the internal components and provides a way to mount the device. 5. Input output I O ports: The VDU may have one or more I O ports that allow it to receive data or signals from other devices, such as a computer or a cable TV box. 6. Power supply: Most VDUs require a source of power, which may be supplied through a power cord or a built-in battery. Functions of Visual Display Unit Some specific functions of a VDU include: 1. Displaying text and graphics: VDUs use a screen to display text and graphics, which can include text documents, spreadsheets, websites, and more. 2.
Functions of Visual Display Unit Some specific functions of a VDU include: 1. Displaying text and graphics: VDUs use a screen to display text and graphics, which can include text documents, spreadsheets, websites, and more. 2. Providing a visual interface: VDUs allow users to interact with a computer or other device by providing a visual interface through which users can see and understand the information being processed and input commands and data. 3. Allowing for multitasking: VDUs allow users to work on multiple tasks at the same time by displaying multiple windows or programs on the screen. 4. Supporting high-resolution displays: Some VDUs support highresolution displays, which can provide a more detailed and accurate representation of the information being displayed. 5. Providing connectivity: VDUs may have connectivity options, such as HDMI or DisplayPort, which allow users to connect the VDU to other devices, such as a computer or a television. Uses of Visual Display Unit Visual Display Units VDUs , also known as computer monitors, are used in a wide range of applications. Some common uses of VDUs include: 1. Office work: VDUs are commonly used in office environments to display text documents, spreadsheets, and other business-related information. 2. Education: VDUs are used in classrooms and educational settings to display educational materials and videos, and to allow students to interact with educational software. 3. Entertainment: VDUs are used to display movies, television shows, and video games, and they can also be used to access streaming services like Netflix or Hulu. 4. Gaming: VDUs are often used in conjunction with gaming consoles or PC gaming systems to display video games. 5. Design and graphics: VDUs are used by designers and graphic artists to create and edit graphics and other visual content. 6. Medical and scientific research: VDUs are used in medical and scientific research to display data and images, such as MRI scans or microscopy images. 7. Military and aviation: VDUs are used in military and aviation applications to display maps, navigation information, and other data. 8. Industrial and manufacturing: VDUs are used in industrial and manufacturing settings to display production data, machine status, and other information. Benefits of Visual Display Unit Visual Display Units VDUs , also known as computer monitors, offer a number of benefits, including: 1.
8. Industrial and manufacturing: VDUs are used in industrial and manufacturing settings to display production data, machine status, and other information. Benefits of Visual Display Unit Visual Display Units VDUs , also known as computer monitors, offer a number of benefits, including: 1. Improved productivity: VDUs allow users to work more efficiently by providing a clear and easy-to-read display of text and graphics. 2. Multitasking: VDUs allow users to work on multiple tasks at the same time by displaying multiple windows or programs on the screen. 3. High-resolution displays: Some VDUs support high-resolution displays, which can provide a more detailed and accurate representation of the information being displayed. 4. Connectivity: VDUs may have connectivity options, such as HDMI or Display Port, which allow users to connect the VDU to other devices, such as a computer or a television. 5. Easy to use: VDUs are generally easy to use, with simple controls and an intuitive interface. 6. Energy efficient: Many modern VDUs are energy efficient, which can help reduce electricity consumption and reduce the environmental impact of using a computer. 7. Customization: VDUs can be customized to meet the specific needs of the user, such as adjusting the display settings to reduce eye strain or to optimize the display for specific tasks. 8. Access to information: VDUs allow users to access a vast amount of information and data that is stored on computers, which can be useful for research, education, and more. Limitations of Visual Display Units VDUs Visual Display Units VDUs , also known as computer monitors, have a few limitations, including: 1. Limited viewing angles: Some VDUs have limited viewing angles, which means that the display may appear distorted or washed out if viewed from certain angles. 2. Limited display size: The size of a VDU is limited by the size of the screen, which may not be large enough to display certain types of information or graphics. 3. Limited color depth: Some VDUs may not support a wide range of colors, which can impact the accuracy and quality of the display. 4. Limited refresh rate: The refresh rate of a VDU refers to how often the display is updated, and a lower refresh rate can result in a less smooth and responsive display. 5.
4. Limited refresh rate: The refresh rate of a VDU refers to how often the display is updated, and a lower refresh rate can result in a less smooth and responsive display. 5. Limited resolution: The resolution of a VDU refers to the number of pixels on the screen, and a lower resolution can result in a less detailed and accurate display. 6. Limited lifespan: Like all electronic devices, VDUs have a limited lifespan and may need to be replaced after a certain period of time. 7. Cost: VDUs can be expensive, particularly high-end models with advanced features. 8. Environmental impact: The production and disposal of VDUs can have an impact on the environment, as they contain materials and chemicals that can be harmful if not properly managed. Hazards of Visual Display Unit There are a few potential hazards associated with using Visual Display Units VDUs , also known as computer monitors, including: 1. Eye strain: Prolonged use of a VDU can cause eye strain, which can cause symptoms such as dry eyes, blurred vision, and headache. 2. Repetitive strain injury: Repetitive actions, such as typing or using a mouse, can cause repetitive strain injuries, such as carpal tunnel syndrome. 3. Back pain: Poor posture while using a VDU can cause back pain, particularly if the workstation is not set up correctly. 4. Electromagnetic fields: Some VDUs emit electromagnetic fields, which have been linked to an increased risk of cancer and other health problems. However, the risks associated with electromagnetic fields from VDUs are generally considered to be low. EXAMPLES OF VDULCD vs LED Displays: The Differences When it comes to choosing between LCD and LED displays, the decision can often be confusing. At first glance, they may seem identical, but there are key differences in their construction, performance, and energy efficiency. In simple terms, LED displays are a type of LCD with a unique backlighting system, and they tend to offer better image quality and power efficiency than standard LCDs. LCD Displays LCD, which stands for Liquid Crystal Display, utilizes a panel of liquid crystal molecules to create images. These molecules twist and untwist to control the amount of light passing through them. However, they do not produce light on their own. Instead, they use a separate backlight or reflector to illuminate the liquid crystals. The backlight in traditional LCD panels is often a Cold Cathode Fluorescent Lamp CCFL .
However, they do not produce light on their own. Instead, they use a separate backlight or reflector to illuminate the liquid crystals. The backlight in traditional LCD panels is often a Cold Cathode Fluorescent Lamp CCFL . While these displays offer good image quality, they have some limitations. Generally, they consume more power and are bulkier than their LED counterparts. Moreover, they may not provide as high contrast or as vibrant colors. LED Displays LED, or Light Emitting Diode displays, are essentially a type of LCD display. The key difference lies in the backlighting system. Instead of using CCFL, LEDdisplays use tiny light-emitting diodes to illuminate the liquid crystals. This change in lighting source opens up a range of benefits. Firstly, LED displays are more energy efficient. LEDs consume less power than CCFL, making them a greener choice. Secondly, they allow for a slimmer and lighter design, making them ideal for modern, sleek devices. One of the critical advantages of LED displays is the potential for greater picture quality. In LED displays, the diodes can be dimmed or brightened individually. This feature, known as local dimming, enhances the contrast ratio, making blacks appear deeper and whites brighter. Consequently, images are more vibrant and lifelike. PRINTERS Different Types of Printers and Their Functions: What Are the Types of Printers? Thermal Transfer Printers Thermal printers use heat to create an image on special thermal paper. They provide direct thermal and thermal transfer, and they re commonly used in receipt printers, shipping label printers, and fax machines. Additionally, they re fast, quiet, and don t require ink or toner. However, the print quality of a thermal printer may fade, and the paper can be expensive. Dye-Sublimation PrintersDye-sublimation printers use heat to transfer dye onto special paper or other materials like fabric or plastic. They re popular for high-quality photo printing and creating customized items like mugs and T-shirts. Additionally, they produce vibrant, long-lasting prints with excellent color accuracy, but the cost of consumables ink and paper can be relatively high. And they re not ideal for standard office documents. 3D Printers 3D printers create three-dimensional objects by layering material often plastic on top of itself based on a digital 3D model.
The best part? UV printing offers vibrant colors and durability on various surfaces. However, initial equipment costs can be high, and maintenance may be needed to keep the printer functioning optimally. Digital Presses Digital presses make a great choice for commercial printing and publishing. They re high-volume printing machines suitable for large quantities of books, brochures, and other printed materials. They offer fast, consistent, high-quality printing for large print runs. However, they re expensive and may require specialized training to operate effectively. In summary, there s a wide array of printers, each designed for specific purposes and printing needs. Choosing the right printer depends on the type of documents or images you need to print, the printing volume, and your budget. Consider your requirements carefully to select the printer that best suits your needs, whether for everyday home use, office tasks, creative projects, or industrial applications. Other Types of Printers 9. Plotters HP 9862A Calculator Plotter Example: HP Design Jet T210 A plotter prints vector graphics by drawing lines on paper using a pen. Some plotters use markers to draw multiple, continuous lines onto paper, while some use knives to cut a material like leather or vinyl. The latter is called cutting plotters. These devices have been phased out by computer-controlled printing machines. However, cutting plotters are still used in many industries. Pros Prints on large sheets of paper with high resolution Draws a single pattern more than one thousand times with no degradation Works with various materials, including cardboard, plywood, plastic, and aluminum Cons Expensive and larger than a conventional printer 8. Impact Printers The impact printer physically presses an inked ribbon against the page. Its plastic or metal head strikes the ink ribbon, whereby the ribbon is pressed against the page, and the specific character impression is printed on the paper. Although this mechanism is quite old, impact printers are still widely used in workplaces and industries. Many different types of impact printers have been developed to date. The most common ones are:8.1 Line Printers IBM 1403 line printer Example: Printronix P7-1500N line matrix printer As the name suggests, Line printers print one line of text at a time the full width of the page . They use a continuous feed of paper instead of individual cut sheets. And they can print up to 2,500 lines per minute.