IGCSE Computer Science: Hardware Concepts

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to Lesson

Podcast

Play an AI-generated podcast conversation about this lesson
Download our mobile app to listen on the go
Get App

Questions and Answers

What is the role of the CPU?

To process data and instructions by carrying out a fetch-decode-execute cycle.

What is a microprocessor?

A microchip installed on an integrated circuit that processes instructions.

What does the von Neumann architecture consist of?

  • Control unit (CU)
  • Arithmetic logical unit (ALU)
  • Main memory (RAM)
  • Inputs and outputs

What is the von Neumann architecture based on?

<p>Based on the stored program concept.</p>
Signup and view all the answers

What in the von Neumann architecture is stored in the same memory in binary form?

<p>Instruction data and program data.</p>
Signup and view all the answers

What registers does the von Neumann architecture consist of?

<ul> <li>Program counter (PC)</li> <li>Memory address register (MAR)</li> <li>Memory data register (MDR)</li> <li>Accumulator (ACC)</li> </ul>
Signup and view all the answers

What is the role of the CU?

<p>Decodes instructions using an instruction set and sends control signals to manage the flow of data and instructions within the CPU.</p>
Signup and view all the answers

What is the role of the ALU?

<p>Performs operations and logical decisions on data.</p>
Signup and view all the answers

What is the role of the PC?

<p>Holds the address of the next instruction to be fetched from memory.</p>
Signup and view all the answers

What is the role of the MAR?

<p>Holds the memory address of the data that is to be fetched from or written to.</p>
Signup and view all the answers

What is the role of the MDR?

<p>Holds the data that has been fetched from memory, or is about to be written to memory.</p>
Signup and view all the answers

What is the role of the ACC?

<p>A register built into the ALU that stores the interim values of calculations.</p>
Signup and view all the answers

What is the role of the CIR?

<p>Holds the current instruction to be decoded and executed.</p>
Signup and view all the answers

What is the role of the address bus?

<p>Carries the addresses of data that needs to be read from or written to.</p>
Signup and view all the answers

What is the role of the data bus?

<p>Carries the actual data or instructions.</p>
Signup and view all the answers

What is the role of the control bus?

<p>Carries control signals transmitted by the CU to the other components.</p>
Signup and view all the answers

What are the steps of the fetch stage?

<ol> <li>PC points to the address of the next instruction to be fetched</li> <li>The address in the PC is copied to the MAR</li> <li>The MAR sends the address to the RAM via the address bus</li> <li>The data stored in the memory are copied into the MDR via the data bus</li> <li>The data stored in the MDR is copied into the CIR</li> <li>The PC increments by 1</li> </ol>
Signup and view all the answers

What occurs in the decode stage?

<p>The instructions in the CIR are decoded by the CU using an instruction set.</p>
Signup and view all the answers

What occurs in the execute stage?

<ul> <li>The instruction is carried out e.g. performing a calculation</li> <li>Depending on the instruction, data may end up being copied into the ALU and/or ACC</li> </ul>
Signup and view all the answers

What is clock speed?

<p>The number of fetch-decode-execute cycles the CPU can perform per second.</p>
Signup and view all the answers

What is clock speed controlled by?

<p>The CPU's internal clock, synchronises operations.</p>
Signup and view all the answers

How does clock speed affect CPU performance?

<p>The higher the clock speed, the greater the number of instructions that can be carried out per second, increasing performance.</p>
Signup and view all the answers

What is the cache?

<p>The cache is very fast to access, volatile memory in the CPU that stores frequently used instructions and data.</p>
Signup and view all the answers

How does larger cache size affect performance?

<p>Reduces the need to fetch instructions and data from memory; if more instructions can be stored, more time can be saved, increasing performance.</p>
Signup and view all the answers

What is a core?

<p>A complete copy of a CPU, with all the components.</p>
Signup and view all the answers

How does number of cores affect performance?

<ul> <li>The more cores a computer has, the more multitasking a computer can do, increasing performance</li> <li>Cores need to communicate with each other, potentially taking time and decreasing performance if not managed well.</li> </ul>
Signup and view all the answers

What code can a CPU execute?

<p>Machine code (binary).</p>
Signup and view all the answers

What is an instruction set?

<p>Specific binary instructions that a CPU can understand and decode.</p>
Signup and view all the answers

What is a property of machine code?

<p>Machine code produced for one computer won't work with another; it is machine specific.</p>
Signup and view all the answers

What is assembly language?

<p>Mnemonics used to represent machine code and make it easier to understand e.g. LDA.</p>
Signup and view all the answers

What is an embedded system?

<p>A computer system constructed within a device that carries out a specific task.</p>
Signup and view all the answers

What are properties of an embedded system?

<ul> <li>Low power consumption</li> <li>Small size</li> <li>Low cost per unit</li> </ul>
Signup and view all the answers

What are examples of embedded systems?

<ul> <li>Dishwashers</li> <li>Microwaves</li> <li>Traffic lights</li> </ul>
Signup and view all the answers

What are the uses of a barcode scanner?

<ul> <li>Scanning goods at a supermarket checkout</li> <li>Tracking packages out for delivery</li> </ul>
Signup and view all the answers

Why is a barcode scanner used?

<ul> <li>For faster checkouts</li> <li>Reduces human error</li> </ul>
Signup and view all the answers

How does a barcode scanner work?

<p>A laser is shined on a barcode made of black and white lines of different thickness. White lines reflect light while black lines absorb more and reflect less. A microprocessor calculates the strength of the reflection and gives it a binary value.</p>
Signup and view all the answers

What are the uses of a digital camera?

<ul> <li>Integrated into all smartphones</li> <li>Can take professional photos</li> <li>Security and surveillance systems</li> </ul>
Signup and view all the answers

Why is a digital camera used?

<ul> <li>Instant photos, no development required</li> <li>Digital photos can be transmitted easily over WiFi</li> <li>Embedded software can be used to adjust photos</li> </ul>
Signup and view all the answers

How does a digital camera work?

<p>Light enters the camera and shines on a sensor (like a CCD or CMOS sensor) made up of many pixels. Each pixel measures light intensity. A microprocessor coverts this into digital data representing colour values.</p>
Signup and view all the answers

How does a keyboard work?

<p>Each character on a keyboard has a corresponding character set value (e.g., ASCII or Unicode). Key presses complete circuits under the keys, generating signals which are converted into digital data representing the character, which the computer interprets.</p>
Signup and view all the answers

How does an optical mouse work?

<p>Uses a red LED or laser and a sensor (like a small camera) to take rapid images of the surface underneath. A microprocessor analyses changes between images to determine the speed and direction of movement, replicating it with the cursor on screen.</p>
Signup and view all the answers

What are the uses of a microphone?

<ul> <li>Music recording</li> <li>Dictation</li> <li>Security</li> <li>Voice calls/communication</li> </ul>
Signup and view all the answers

Why is a microphone used?

<ul> <li>To capture any real world sound</li> <li>Sound can then be modified, stored, or transmitted digitally</li> </ul>
Signup and view all the answers

How does a microphone work?

<p>Vibrations caused by sound waves cause a diaphragm and an attached component (like a coil in a dynamic microphone) to move. This movement creates changes in an electrical property (e.g., changes in an electromagnetic field or capacitance). These tiny electrical changes are converted by electronics (often including an ADC) into digital data.</p>
Signup and view all the answers

What are the uses of QR codes?

<ul> <li>Advertising products</li> <li>Quick links to websites</li> <li>Electronic travel passes</li> <li>Contactless payments</li> </ul>
Signup and view all the answers

Why are QR codes used?

<p>Holds far more information than a traditional barcode.</p>
Signup and view all the answers

How do QR codes work?

<p>Read using a scanner (typically a camera on a phone). An app processes the image, identifying the pattern of black and white squares according to the QR standard, and converts the pattern into readable data (like a URL, text, or contact info).</p>
Signup and view all the answers

What are the three different types of touchscreen?

<ul> <li>Capacitive</li> <li>Infra-red</li> <li>Resistive</li> </ul>
Signup and view all the answers

How do capacitive touch screens work?

<p>Composed of a protective layer, transparent conductive layer (often Indium Tin Oxide - ITO), and a glass substrate. The human body is conductive; touching the screen with a bare finger or conductive stylus draws a small amount of current, changing the electrostatic field at that point. Sensors detect this change.</p>
Signup and view all the answers

Where are capacitive touch screens used?

<ul> <li>Tablets</li> <li>Laptops</li> <li>Smartphones</li> </ul>
Signup and view all the answers

What are the advantages of capacitive touch screens?

<ul> <li>Excellent image quality (transparent layers)</li> <li>High precision and responsiveness</li> <li>Durable screen surface</li> <li>Allows multiple touches at the same time (multi-touch)</li> </ul>
Signup and view all the answers

What is the disadvantage of capacitive touch screens?

<p>Requires a conductive object (like a finger or special stylus) to activate; doesn't work with gloves or non-conductive styluses.</p>
Signup and view all the answers

How do infra-red touch screens work?

<p>LEDs along one or two edges shine infra-red light across the screen surface to sensors on the opposite edges, forming a grid or matrix of invisible light beams. When the screen is touched by any object (finger, gloved hand, stylus), it breaks the beams at that location, allowing the system to determine the touch coordinates.</p>
Signup and view all the answers

Where are infra-red touch screens used?

<ul> <li>Large scale commercial displays</li> <li>Large information kiosks</li> <li>Medical equipment</li> <li>Some ATMs</li> </ul>
Signup and view all the answers

What are the advantages of infra-red touch screens?

<ul> <li>Excellent image quality (no layers over the display)</li> <li>Unlimited touch life (no physical wear from touch)</li> <li>Scales very well to large sizes</li> <li>Can be activated by any object</li> </ul>
Signup and view all the answers

What is the disadvantage of infra-red touch screens?

<p>Sensitive to interference from ambient light, dust, water, snow etc., which can cause false touches or prevent detection.</p>
Signup and view all the answers

How do resistive touch screens work?

<p>Consists of two flexible conductive layers (often coated plastic) separated by a small air gap or insulating dots. The top layer is typically made of a flexible polyester material. When the screen is pressed, the top layer flexes and makes physical contact with the bottom layer at the point of pressure, completing a circuit. The voltage change is measured to determine the touch coordinates.</p>
Signup and view all the answers

Where are resistive touch screens used?

<ul> <li>Cash machines (ATMs)</li> <li>Information kiosks</li> <li>Medical equipment</li> <li>Older handheld consoles (e.g., Nintendo DS)</li> </ul>
Signup and view all the answers

What are the advantages of resistive touch screens?

<ul> <li>Cheap to produce</li> <li>Can be activated using any object (finger, gloved hand, stylus, pen cap)</li> <li>Very resistant to surface contaminants (dust, liquids)</li> </ul>
Signup and view all the answers

What is the disadvantage of resistive touch screens?

<p>Lower image clarity (due to multiple layers), lower precision, less responsive feel compared to capacitive, and typically only supports single touch.</p>
Signup and view all the answers

What are the uses of 2D scanners?

<ul> <li>Creating digital versions of documents and photos</li> <li>Reading passports at airports</li> <li>Digitizing artwork</li> </ul>
Signup and view all the answers

What are the uses of 3D scanners?

<ul> <li>Creating 3D models with CAD software</li> <li>Dentistry (creating models of teeth)</li> <li>Reverse engineering</li> <li>Quality control</li> </ul>
Signup and view all the answers

Why are scanners used?

<p>Simple, cheap and effective way of generating digital representations of objects (2D or 3D).</p>
Signup and view all the answers

How do 2D scanners work?

<p>Typically, a light source illuminates the document placed on a glass plate. A scan head containing a light sensor (like a CCD array) moves across the document, capturing the reflected light line by line. The intensity and colour of the reflected light are measured and converted into digital pixel data to create an image.</p>
Signup and view all the answers

How do 3D scanners work?

<p>Various technologies exist. Many shine a laser line or pattern onto the object's surface. Cameras observe the deformation of the light pattern caused by the object's shape. By analyzing this deformation from different angles, the scanner calculates the 3D coordinates (geometry) of points on the object's surface, creating a digital 3D model (point cloud or mesh).</p>
Signup and view all the answers

What are actuators used for?

<ul> <li>Starting and stopping a pump</li> <li>Opening and closing an automatic door</li> <li>Turning a wheel</li> <li>Moving robotic arms</li> </ul>
Signup and view all the answers

What do actuators do?

<p>Convert energy (usually electrical, hydraulic, or pneumatic) into physical motion (linear or rotary).</p>
Signup and view all the answers

What are DLP projectors used for?

<ul> <li>Projecting a computer output onto a screen, wall, or other surface</li> <li>Used in personal (home cinema) and professional (presentations, cinemas) settings</li> </ul>
Signup and view all the answers

How do DLP projectors work?

<p>Use a Digital Micromirror Device (DMD) chip containing many tiny mirrors arranged in a matrix, where each mirror represents a pixel. White light is shone onto the DMD. Mirrors rapidly tilt towards or away from the light source to turn pixels on or off. Light passing through a rotating colour wheel (for single-chip DLP) or separated by prisms (for three-chip DLP) creates the colour image, which is then projected through a lens.</p>
Signup and view all the answers

What are the advantages of DLP over LCD projectors?

<ul> <li>Higher contrast ratios (deeper blacks)</li> <li>Smoother video (less motion blur)</li> <li>Smaller, lighter and more portable (especially single-chip models)</li> </ul>
Signup and view all the answers

What are LCD projectors used for?

<p>Projecting a computer output onto a screen, wall, or other surface, similar to DLP projectors. Common in business presentations and educational settings.</p>
Signup and view all the answers

How do LCD projectors work?

<p>Use three small LCD panels (one each for Red, Green, and Blue). White light from the lamp is split into RGB components using dichroic mirrors. Each colour component passes through its corresponding LCD panel, which modulates the light pixel by pixel to create the image component for that colour. The three colour images are then recombined using a prism and passed through a lens for projection.</p>
Signup and view all the answers

What are the advantages of LCD over DLP projectors?

<ul> <li>Sharper image (pixels may appear more distinct)</li> <li>Better colour saturation and accuracy</li> <li>Typically more light-efficient (brighter image for the same lamp wattage)</li> <li>Typically less expensive for comparable specifications</li> </ul>
Signup and view all the answers

What are inkjet printers used for?

<ul> <li>Small scale print jobs (home, small office)</li> <li>Cheaper initial purchase price and smaller size, popular for personal use</li> <li>Excellent for printing out high quality photos on special paper</li> </ul>
Signup and view all the answers

How do inkjet printers work?

<p>Spray tiny droplets of liquid ink from print head nozzles directly onto paper. Different methods are used to eject the ink, such as thermal (heating ink to create a bubble that forces a droplet out) or piezoelectric (using crystals that change shape when voltage is applied, squeezing ink out).</p>
Signup and view all the answers

What are laser printers used for?

<ul> <li>High quality, inexpensive text printing</li> <li>Very fast and accurate for non-colour documents and images</li> <li>Often has a lower running cost per page compared to inkjet printers, suitable for high volume printing (offices)</li> </ul>
Signup and view all the answers

How do laser printers work?

<p>Use toner cartridges, which contain fine powder (toner). A laser beam 'draws' the image onto a photosensitive drum, creating negatively charged areas. The drum rotates and picks up positively charged toner particles onto the charged areas. The toner image is then transferred from the drum to the paper, and finally bonded (fused) to the paper using heat and pressure.</p>
Signup and view all the answers

What are LCDs used for?

<ul> <li>TVs, monitors, laptops, mobile devices</li> <li>Gradually being phased out or supplemented by newer technologies like LED (backlit LCD) and OLED in many applications.</li> </ul>
Signup and view all the answers

How do LCD screens work?

<p>Made up of many tiny liquid crystals arranged in a grid (matrix) between two layers of polarized glass. The crystals can twist or untwist when an electrical voltage is applied. This twisting affects whether polarized light from a backlight can pass through the second polarizing filter. By controlling the voltage applied to each crystal (pixel), the screen can create images. Colour filters are used over sub-pixels for colour displays.</p>
Signup and view all the answers

What are LED displays used for?

<ul> <li>Replacing traditional LCDs (usually as LED-backlit LCDs) in TVs, monitors, and laptops</li> <li>True LED displays (Direct View LED) where each pixel is an LED are used for very large displays e.g. concerts, sporting events, billboards, festivals</li> </ul>
Signup and view all the answers

How do LED displays work?

<p>This depends on the type. <strong>LED-backlit LCDs</strong> work like standard LCDs but use Light Emitting Diodes (LEDs) for the backlight instead of older CCFL tubes. <strong>True LED displays</strong> (like OLED or MicroLED) use tiny individual LEDs for each pixel (or sub-pixel). These LEDs emit their own light, so no separate backlight is needed.</p>
Signup and view all the answers

Why are LED displays generally considered better than older CCFL-backlit LCDs?

<ul> <li>Offer better image quality (brightness, contrast) and wider viewing angles</li> <li>Have a longer lifespan</li> <li>Require no separate backlighting (if true LED) or use more efficient LED backlighting, allowing for thinner and lighter designs and lower power consumption.</li> </ul>
Signup and view all the answers

How do speakers work?

<p>A digital audio signal passes through a Digital-to-Analogue Converter (DAC) to become an analogue electrical signal. This signal is often boosted by an amplifier. The amplified signal is passed to the speaker driver, typically an electromagnet (voice coil) attached to a cone. The changing electrical signal causes the electromagnet to move back and forth within a permanent magnet field, vibrating the cone and producing analogue sound waves in the air.</p>
Signup and view all the answers

What are 3D printers used for?

<ul> <li>Rapid prototyping (creating physical models quickly)</li> <li>Manufacturing custom or spare parts</li> <li>Creating inexpensive prosthetics or medical models</li> <li>Hobbyist creations</li> </ul>
Signup and view all the answers

How do 3D printers work?

<p>Most common types (like FDM - Fused Deposition Modeling) deposit layers of material (like plastic filament melted through a nozzle) on top of each other according to a digital 3D model. The printer head moves precisely to build up the object layer by layer from the bottom up.</p>
Signup and view all the answers

What are sensors?

<p>Input devices that measure physical properties in the environment (like temperature, light, pressure, motion) and convert these measurements into electrical signals, often then converted into digital data.</p>
Signup and view all the answers

What device converts an analogue signal to a digital signal?

<p>An Analogue-to-Digital Converter (ADC).</p>
Signup and view all the answers

What device converts a digital signal to an analogue signal?

<p>A Digital-to-Analogue Converter (DAC).</p>
Signup and view all the answers

What are the types of primary storage?

<ul> <li>RAM (Random Access Memory)</li> <li>ROM (Read-Only Memory)</li> <li>Registers (within the CPU)</li> <li>Cache (within or close to the CPU)</li> </ul>
Signup and view all the answers

What does secondary storage do?

<p>Stores data, programs, and the Operating System (OS) for future use, typically when the computer is turned off.</p>
Signup and view all the answers

What are types of secondary storage?

<ul> <li>Optical storage (CD, DVD, Blu-ray)</li> <li>Magnetic storage (Hard Disk Drive - HDD, Magnetic Tape)</li> <li>Solid State storage (Solid State Drive - SSD, USB flash drive, SD card)</li> </ul>
Signup and view all the answers

What are the features of primary storage?

<ul> <li>Mostly volatile (except ROM), lose all data held when the power is switched off</li> <li>Smaller storage capacity compared to secondary storage</li> <li>Physically close to the CPU, allowing much faster access speeds</li> </ul>
Signup and view all the answers

What are the features of secondary storage?

<ul> <li>Non-volatile, retain data even when there is no power</li> <li>Much greater storage capacity compared to primary storage</li> <li>Physically farther away from the CPU, resulting in slower access speeds</li> </ul>
Signup and view all the answers

What is the ROM and its function?

<p>ROM (Read-Only Memory) is a small piece of non-volatile primary storage located on the motherboard. It contains essential startup instructions (firmware) for the computer, such as loading the Basic Input/Output System (BIOS) or UEFI, performing initial hardware checks (POST), and bootstrapping the operating system.</p>
Signup and view all the answers

What is the RAM and its function?

<p>RAM (Random Access Memory) is a volatile, temporary read/write primary storage device with fast access speeds. It stores the operating system, programs, and data that are currently being used or processed by the CPU. Volatile means its contents are lost when power is turned off.</p>
Signup and view all the answers

What are examples of things stored in the RAM for access by the CPU?

<ul> <li>The Operating System (OS) components currently needed</li> <li>Application programs that are running (e.g., web browser, games, word processor)</li> <li>Data currently being used by those applications (e.g., open documents, data being downloaded/buffered, clipboard contents)</li> </ul>
Signup and view all the answers

What are the uses of secondary storage?

<ul> <li>Storing programs (applications) and data that are not currently in use, or when the computer is turned off</li> <li>Storing the Operating System itself</li> <li>Backing up or archiving data for safety or long-term storage</li> </ul>
Signup and view all the answers

What are examples of optical storage?

<ul> <li>CDs (Compact Discs)</li> <li>DVDs (Digital Versatile Discs)</li> <li>Blu-ray Discs</li> </ul>
Signup and view all the answers

How does optical storage work?

<p>A laser beam shines on the reflective surface of the disc. The surface has microscopic pits (indentations) and lands (flat areas) arranged in a spiral track. The laser reflects differently off pits and lands. A sensor detects these changes in reflection, which are interpreted as binary data (1s and 0s).</p>
Signup and view all the answers

What are the advantages of optical storage?

<ul> <li>Cheap to manufacture (per disc)</li> <li>Lightweight and portable</li> <li>Relatively durable if handled carefully</li> </ul>
Signup and view all the answers

What is the role of the CPU?

<p>To process data and instructions by carrying out a fetch-decode-execute cycle</p>
Signup and view all the answers

What is a microprocessor?

<p>A microchip installed on an integrated circuit that processes instructions</p>
Signup and view all the answers

What does the von Neumann architecture consist of?

<ul> <li>Control unit (CU)</li> <li>Arithmetic logical unit (ALU)</li> <li>Main memory (RAM)</li> <li>Inputs and outputs</li> </ul>
Signup and view all the answers

What is the von Neumann architecture based on?

<p>Based on the stored program concept</p>
Signup and view all the answers

What in the von Neumann architecture is stored in the same memory in binary form?

<p>Instruction data and program data</p>
Signup and view all the answers

What registers does the von Neumann architecture consist of?

<ul> <li>Program counter (PC)</li> <li>Memory address register (MAR)</li> <li>Memory data register (MDR)</li> <li>Accumulator</li> </ul>
Signup and view all the answers

What is the role of the CU?

<p>Decodes instructions using an instruction set and sends control signals to manage the flow of data and instructions within the CPU</p>
Signup and view all the answers

What is the role of the ALU?

<p>Performs operations and logical decisions on data</p>
Signup and view all the answers

What is the role of the PC?

<p>Holds the address of the next instruction to be fetched from memory</p>
Signup and view all the answers

What is the role of the MAR?

<p>Holds the memory address of the data that is to be fetched from or written to</p>
Signup and view all the answers

What is the role of the MDR?

<p>Holds the data that has been fetched from memory, or is about to be written to memory</p>
Signup and view all the answers

What is the role of the ACC?

<p>A register built into the ALU that stores the interim values of calculations</p>
Signup and view all the answers

What is the role of the CIR?

<p>Holds the current instruction to be decoded and executed</p>
Signup and view all the answers

What is the role of the address bus?

<p>Carries the addresses of data that needs to be read from or written to</p>
Signup and view all the answers

What is the role of the data bus?

<p>Carries the actual data or instructions</p>
Signup and view all the answers

What is the role of the control bus?

<p>Carries control signals transmitted by the CU to the other components</p>
Signup and view all the answers

What are the steps of the fetch stage?

<ol> <li>PC points to the address of the next instruction to be fetched</li> <li>The address in the PC is copied to the MAR</li> <li>The MAR sends the address to the RAM via the address bus</li> <li>The data stored in the memory are copied into the MDR via the data bus</li> <li>The data stored in the MDR is copied into the CIR</li> <li>The PC increments by 1</li> </ol>
Signup and view all the answers

What occurs in the decode stage?

<p>The instructions in the CIR are decoded by the CU using an instruction set</p>
Signup and view all the answers

What occurs in the execute stage?

<ul> <li>The instruction is carried out e.g. performing a calculation</li> <li>Depending on the instruction, data may end up being copied into the ALU and/or ACC</li> </ul>
Signup and view all the answers

What is clock speed?

<p>The number of fetch-decode-execute cycles the CPU can perform per second</p>
Signup and view all the answers

What is clock speed controlled by?

<p>The CPU's internal clock, synchronises operations</p>
Signup and view all the answers

How does clock speed affect CPU performance?

<p>The higher the clock speed, the greater the number of instructions that can be carried out per second, increasing performance</p>
Signup and view all the answers

What is the cache?

<p>The cache is very fast to access, volatile memory in the CPU that stores frequently used instructions and data</p>
Signup and view all the answers

How does larger cache size affect performance?

<p>Reduces the need to fetch instructions and data from memory, if more instructions can be stored more time can be saved, increasing performance</p>
Signup and view all the answers

What is a core?

<p>A complete copy of a CPU, with all the components</p>
Signup and view all the answers

How does number of cores affect performance?

<ul> <li>The more cores a computer has, the more multitasking a computer can do, increasing performance</li> <li>Cores need to communicate with each other, taking time and decreasing performance</li> </ul>
Signup and view all the answers

What code can a CPU execute?

<p>Machine code (binary)</p>
Signup and view all the answers

What is an instruction set?

<p>Specific binary instructions that a CPU can understand and decode</p>
Signup and view all the answers

What is a property of machine code?

<p>Machine code produced for one computer won't work with another, it is machine specific</p>
Signup and view all the answers

What is assembly language?

<p>Mnemonics used to represent machine code and make it easier to understand e.g. LDA</p>
Signup and view all the answers

What is an embedded system?

<p>A computer system constructed within a device that carries out a specific task</p>
Signup and view all the answers

What are properties of an embedded system?

<ul> <li>Low power consumption</li> <li>Small size</li> <li>Low cost per unit</li> </ul>
Signup and view all the answers

What are examples of embedded systems?

<ul> <li>Dishwashers</li> <li>Microwaves</li> <li>Traffic lights</li> </ul>
Signup and view all the answers

What are the uses of a barcode scanner?

<ul> <li>Scanning goods at a supermarket checkout</li> <li>Tracking packages out for delivery</li> </ul>
Signup and view all the answers

Why is a barcode scanner used?

<ul> <li>For faster checkouts</li> <li>Reduces human error</li> </ul>
Signup and view all the answers

How does a barcode scanner work?

<ul> <li>Laser is shined on a barcode made of black and white lines of different thickness</li> <li>White lines reflect light while black lines absorb more and reflect less</li> <li>A microprocessor calculates the strength of the reflection and gives it a binary value</li> </ul>
Signup and view all the answers

What are the uses of a digital camera?

<ul> <li>Integrated into all smartphones</li> <li>Can take professional photos</li> <li>Security and surveillance systems</li> </ul>
Signup and view all the answers

Why is a digital camera used?

<ul> <li>Instant photos, no development required</li> <li>Digital photos can be transmitted easily over WiFi</li> <li>Embedded software can be used to adjust photos</li> </ul>
Signup and view all the answers

How does a digital camera work?

<ul> <li>Light enters the camera and shines on a sensor made up of many pixels</li> <li>Each pixel measures light intensity</li> <li>A microprocessor converts this into digital data representing colour values</li> </ul>
Signup and view all the answers

How does a keyboard work?

<ul> <li>Each character on a keyboard has a corresponding character set value</li> <li>Key presses are converted into digital signals which the computer interprets</li> </ul>
Signup and view all the answers

How does an optical mouse work?

<ul> <li>Uses a red LED and a sensor to determine the movement of the mouse relative to the surface</li> <li>Microprocessor analyses both speed and movement, replicating it on screen</li> </ul>
Signup and view all the answers

What are the uses of a microphone?

<ul> <li>Music recording</li> <li>Dictation</li> <li>Security</li> </ul>
Signup and view all the answers

Why is a microphone used?

<ul> <li>To capture any real world Tsound</li> <li>Sound can then be modified</li> </ul>
Signup and view all the answers

How does a microphone work?

<ul> <li>Vibrations caused by sound waves cause a coil to move around a magnet</li> <li>This results in electromagnetic field changes</li> <li>Tiny changes converted by a microprocessor and ADC into digital data</li> </ul>
Signup and view all the answers

What are the uses of QR codes?

<ul> <li>Advertising products</li> <li>Quick links to websites</li> <li>Electronic travel passes</li> </ul>
Signup and view all the answers

Why are QR codes used?

<p>Holds far more information than a traditional barcode</p>
Signup and view all the answers

How do QR codes work?

<ul> <li>Read using a scanner (typically a phone)</li> <li>An app processes the image and converts the squares into readable data</li> </ul>
Signup and view all the answers

What are the three different types of touchscreen?

<ul> <li>Capacitive</li> <li>Infra-red</li> <li>Resistive</li> </ul>
Signup and view all the answers

How do capacitive touch screens work?

<ul> <li>Composed of a protective layer, transparent conductive layer and a glass substrate</li> <li>Touching the screen with a bare hand changes the electrostatic field of the transparent layer</li> </ul>
Signup and view all the answers

Where are capacitive touch screens used?

<ul> <li>Tablets</li> <li>Laptops</li> <li>Smartphones</li> </ul>
Signup and view all the answers

What are the advantages of capacitive touch screens?

<ul> <li>Excellent image quality</li> <li>High precision</li> <li>Durable screen that allows multiple touches at the same time</li> </ul>
Signup and view all the answers

What is the disadvantage of capacitive touch screens?

<p>Requires a finger or stylus to activate</p>
Signup and view all the answers

How do infra-red touch screens work?

<ul> <li>LEDs shine infra-red light across a screen, forming a matrix</li> <li>When the screen is touched, the matrix is broken</li> </ul>
Signup and view all the answers

Where are infra-red touch screens used?

<ul> <li>Large scale commercial displays</li> <li>Large information kiosks</li> <li>Medical equipment</li> </ul>
Signup and view all the answers

What are the advantages of infra-red touch screens?

<ul> <li>Excellent image quality</li> <li>Unlimited touch life</li> <li>Scales very well</li> </ul>
Signup and view all the answers

What is the disadvantage of infra-red touch screens?

<p>Sensitive to interference from ambient light, water, snow etc</p>
Signup and view all the answers

How do resistive touch screens work?

<ul> <li>Consists of two conductive layers</li> <li>Top layer is made of a flexible polyester material</li> <li>The two layers are separated by an insulator material</li> <li>When the screen is pressed the two layers connect and complete a circuit</li> </ul>
Signup and view all the answers

Where are resistive touch screens used?

<ul> <li>Cash machines</li> <li>Information kiosks</li> <li>Medical equipment</li> </ul>
Signup and view all the answers

What are the advantages of resistive touch screens?

<ul> <li>Cheap to produce</li> <li>Can be activated using any object</li> <li>Very resistant to surface contaminents</li> </ul>
Signup and view all the answers

What is the disadvantage of resistive touch screens?

<p>Lower image clarity and precision compared to other types</p>
Signup and view all the answers

What are the uses of 2D scanners?

<ul> <li>Creating digital versions of documents and photos</li> <li>Reading passports at airports</li> </ul>
Signup and view all the answers

What are the uses of 3D scanners?

<ul> <li>Creating 3D models with CAD software</li> <li>Dentistry</li> </ul>
Signup and view all the answers

Why are scanners used?

<p>Simple, cheap and effective way of generating digital representations of objects</p>
Signup and view all the answers

How do 2D scanners work?

<ul> <li>Shine a bright light onto across a document</li> <li>Measure the levels of reflected light and creates digital version of it</li> </ul>
Signup and view all the answers

How do 3D scanners work?

<ul> <li>Shine a laser over the surface of an object</li> <li>Records its geometry and creates a digital model of it</li> </ul>
Signup and view all the answers

What are actuators used for?

<ul> <li>Starting and stopping a pump</li> <li>Opening and closing an automatic door</li> <li>Turning a wheel</li> </ul>
Signup and view all the answers

What do actuators do?

<p>Carry out physical movement</p>
Signup and view all the answers

What are DLP projectors used for?

<ul> <li>Projecting a computer output onto a wall etc</li> <li>Personal and professional settings</li> </ul>
Signup and view all the answers

What do DLPs do?

<ul> <li>Use many micro mirrors arranged in a matrix placed on a microchip within the projector</li> <li>White light is shone through a rotating colour filter to produce an image while an angled mirror changes colour intensity</li> </ul>
Signup and view all the answers

What are the advantages of DLPs over LCDs

<ul> <li>Higher contrast ratios</li> <li>Smoother video</li> <li>Smaller, lighter and more portable</li> </ul>
Signup and view all the answers

What are LCD projectors used for?

<p>Same as DLP projectors</p>
Signup and view all the answers

What do LCD projectors do?

<ul> <li>Use 3 mirror filters to separate an image into 3 different wavelengths of colour (RGB)</li> <li>Images are passed through a prism and recombined</li> <li>Full colour image is passed through a lens and projected</li> </ul>
Signup and view all the answers

What are the advantages of LCDs over DLPs

<ul> <li>Sharper image</li> <li>Better colour reproduction</li> <li>Typically less expensive</li> </ul>
Signup and view all the answers

What are inkjet printers used for?

<ul> <li>Small scale print jobs</li> <li>Cheaper and smaller, popular for personal use</li> <li>Excellent for printing out high quality photos</li> </ul>
Signup and view all the answers

What do inkjet printers do?

<p>Force tiny droplets of liquid ink through very fine nozzles onto a sheet of paper</p>
Signup and view all the answers

What are laser printers used for?

<ul> <li>High quality, inexpensive printing</li> <li>Very fast and accurate for non-colour documents and images</li> <li>Lower running cost per page compared to inkjet printer</li> </ul>
Signup and view all the answers

What do laser printers do?

<ul> <li>Use toner cartridges, which contain powdered, charged ink</li> <li>Using a laser, mirror image of the printer page is drawn onto a drum by creating negatively charged areas</li> <li>Drum then picks up positively charged ink particles and bonds them to the paper using heat</li> </ul>
Signup and view all the answers

What are LCDs used for?

<ul> <li>TV's, monitors, laptops, mobile devices</li> <li>Gradually being phased out by LED and OLED</li> </ul>
Signup and view all the answers

What do LCDs do?

<ul> <li>Made up of many tiny liquid crystals</li> <li>Crystals form a matrix of pixels which can be affected by changes in applied electrical fields</li> <li>LCDs require some form of backlighting</li> </ul>
Signup and view all the answers

What are LED displays used for?

<ul> <li>Replacing LCDs in more and more situations</li> <li>Multiple screens can be joined together, ideal for very large displays e.g. concerts, sporting events, festivals</li> </ul>
Signup and view all the answers

What do LED displays do?

<p>Uses tiny LEDs to produce a bright image almost instantly</p>
Signup and view all the answers

Why are LED displays better than LCDs?

<ul> <li>Offer better image quality and viewing angles</li> <li>Has a longer lifespan</li> <li>Requires no additional backlighting so thinner and lighter</li> </ul>
Signup and view all the answers

What do speakers do?

<ul> <li>Digital representation of sound passes through DAC</li> <li>Further boosted by amplifier</li> <li>Passed to a speaker to create analogue sound waves</li> </ul>
Signup and view all the answers

What are 3D printers used for?

<ul> <li>Rapid prototyping</li> <li>Spare parts</li> <li>Inexpensive prosthetics</li> </ul>
Signup and view all the answers

What do 3D printers do?

<p>Deposit layers of material on top of each other to slowly build a 3D project</p>
Signup and view all the answers

What are sensors?

<p>Input devices that measure physical properties in the environment and convert these measurements into digital data</p>
Signup and view all the answers

What device converts an analogue signal to a digital signal?

<p>An analogue to digital converter (ADC)</p>
Signup and view all the answers

What device converts a digital signal to an analogue signal?

<p>A digital to analogue converter (DAC)</p>
Signup and view all the answers

What are the types of primary storage?

<ul> <li>RAM</li> <li>ROM</li> <li>Registers</li> <li>Cache</li> </ul>
Signup and view all the answers

What does secondary storage do?

<p>Stores data, programs and OS for future use</p>
Signup and view all the answers

What are types of secondary storage?

<ul> <li>Optical storage</li> <li>Magnetic storage</li> <li>Solid state storage</li> </ul>
Signup and view all the answers

What are the features of primary storage?

<ul> <li>Volatile, lose all data held when the power is switched off</li> <li>Relatively small storage capacity when compared to secondary storage</li> <li>Physically close to the CPU, faster access speed</li> </ul>
Signup and view all the answers

What are the features of secondary storage?

<ul> <li>Non-volatile, retain data even when there is no power</li> <li>Have much greater storage capacity compared to primary storage</li> <li>Physically farther away from the CPU, slower access speed</li> </ul>
Signup and view all the answers

What is the ROM and its function?

<ul> <li>Small piece of read-only memory located on the motherboard</li> <li>Only primary storage that is non-volatile</li> <li>Contains startup instructions for the computer e.g. loading basic input/output system and checking hardware is installed correctly</li> <li>These instructions are called firmware</li> </ul>
Signup and view all the answers

What is the RAM and its function?

<ul> <li>Temporary read/write storage device close to the CPU that has very fast access speeds</li> <li>Stores instructions and data that are currently being processed by the CPU</li> <li>Holds the OS when the computer is running</li> <li>Volatile</li> </ul>
Signup and view all the answers

What are examples of things stored in the RAM for access by the CPU?

<ul> <li>The OS</li> <li>Programs that are running e.g. web browser, games</li> <li>Data currently in use e.g. data being downloaded/buffered</li> </ul>
Signup and view all the answers

What are the uses of secondary storage?

<ul> <li>Stores programs and data that are not currently in use or when the computer is turned off e.g. the OS</li> <li>Backing up or archiving data</li> </ul>
Signup and view all the answers

What are examples of optical storage?

<ul> <li>CDs</li> <li>DVDs</li> <li>Blu-ray discs</li> </ul>
Signup and view all the answers

How does optical storage work?

<ul> <li>Shines a laser on the disc and process the reflection</li> <li>Uses pits and lands that are physically burnt onto the disc to represent 1s and 0s</li> </ul>
Signup and view all the answers

What are the advantages of optical storage?

<ul> <li>Cheap</li> <li>Lightweight</li> <li>Portable</li> </ul>
Signup and view all the answers

What is the role of the CPU?

<p>To process data and instructions by carrying out a fetch-decode-execute cycle.</p>
Signup and view all the answers

What is a microprocessor?

<p>A microchip installed on an integrated circuit that processes instructions.</p>
Signup and view all the answers

What does the von Neumann architecture consist of?

<ul> <li>Control unit (CU)</li> <li>Arithmetic logical unit (ALU)</li> <li>Main memory (RAM)</li> <li>Inputs and outputs</li> </ul>
Signup and view all the answers

What is the von Neumann architecture based on?

<p>Based on the stored program concept.</p>
Signup and view all the answers

What in the von Neumann architecture is stored in the same memory in binary form?

<p>Instruction data and program data.</p>
Signup and view all the answers

What registers does the von Neumann architecture consist of?

<ul> <li>Program counter (PC)</li> <li>Memory address register (MAR)</li> <li>Memory data register (MDR)</li> <li>Accumulator (ACC)</li> </ul>
Signup and view all the answers

What is the role of the CU?

<p>Decodes instructions using an instruction set and sends control signals to manage the flow of data and instructions within the CPU.</p>
Signup and view all the answers

What is the role of the ALU?

<p>Performs operations and logical decisions on data.</p>
Signup and view all the answers

What is the role of the PC?

<p>Holds the address of the next instruction to be fetched from memory.</p>
Signup and view all the answers

What is the role of the MAR?

<p>Holds the memory address of the data that is to be fetched from or written to.</p>
Signup and view all the answers

What is the role of the MDR?

<p>Holds the data that has been fetched from memory, or is about to be written to memory.</p>
Signup and view all the answers

What is the role of the ACC?

<p>A register built into the ALU that stores the interim values of calculations.</p>
Signup and view all the answers

What is the role of the CIR?

<p>Holds the current instruction to be decoded and executed.</p>
Signup and view all the answers

What is the role of the address bus?

<p>Carries the addresses of data that needs to be read from or written to.</p>
Signup and view all the answers

What is the role of the data bus?

<p>Carries the actual data or instructions.</p>
Signup and view all the answers

What is the role of the control bus?

<p>Carries control signals transmitted by the CU to the other components.</p>
Signup and view all the answers

What are the steps of the fetch stage?

<ol> <li>PC points to the address of the next instruction to be fetched</li> <li>The address in the PC is copied to the MAR</li> <li>The MAR sends the address to the RAM via the address bus</li> <li>The data stored in the memory are copied into the MDR via the data bus</li> <li>The data stored in the MDR is copied into the CIR</li> <li>The PC increments by 1</li> </ol>
Signup and view all the answers

What occurs in the decode stage?

<p>The instructions in the CIR are decoded by the CU using an instruction set.</p>
Signup and view all the answers

What occurs in the execute stage?

<ul> <li>The instruction is carried out e.g. performing a calculation</li> <li>Depending on the instruction, data may end up being copied into the ALU and/or ACC</li> </ul>
Signup and view all the answers

What is clock speed?

<p>The number of fetch-decode-execute cycles the CPU can perform per second.</p>
Signup and view all the answers

What is clock speed controlled by?

<p>The CPU's internal clock, synchronises operations.</p>
Signup and view all the answers

How does clock speed affect CPU performance?

<p>The higher the clock speed, the greater the number of instructions that can be carried out per second, increasing performance.</p>
Signup and view all the answers

What is the cache?

<p>The cache is very fast to access, volatile memory in the CPU that stores frequently used instructions and data.</p>
Signup and view all the answers

How does larger cache size affect performance?

<p>Reduces the need to fetch instructions and data from memory; if more instructions can be stored, more time can be saved, increasing performance.</p>
Signup and view all the answers

What is a core?

<p>A complete copy of a CPU, with all the components.</p>
Signup and view all the answers

How does number of cores affect performance?

<ul> <li>The more cores a computer has, the more multitasking a computer can do, increasing performance</li> <li>Cores need to communicate with each other, taking time and decreasing performance</li> </ul>
Signup and view all the answers

What code can a CPU execute?

<p>Machine code (binary).</p>
Signup and view all the answers

What is an instruction set?

<p>Specific binary instructions that a CPU can understand and decode.</p>
Signup and view all the answers

What is a property of machine code?

<p>Machine code produced for one computer won't work with another; it is machine specific.</p>
Signup and view all the answers

What is assembly language?

<p>Mnemonics used to represent machine code and make it easier to understand e.g. LDA.</p>
Signup and view all the answers

What is an embedded system?

<p>A computer system constructed within a device that carries out a specific task.</p>
Signup and view all the answers

What are properties of an embedded system?

<ul> <li>Low power consumption</li> <li>Small size</li> <li>Low cost per unit</li> </ul>
Signup and view all the answers

What are examples of embedded systems?

<ul> <li>Dishwashers</li> <li>Microwaves</li> <li>Traffic lights</li> </ul>
Signup and view all the answers

What are the uses of a barcode scanner?

<ul> <li>Scanning goods at a supermarket checkout</li> <li>Tracking packages out for delivery</li> </ul>
Signup and view all the answers

Why is a barcode scanner used?

<ul> <li>For faster checkouts</li> <li>Reduces human error</li> </ul>
Signup and view all the answers

How does a barcode scanner work?

<ul> <li>Laser is shined on a barcode made of black and white lines of different thickness</li> <li>White lines reflect light while black lines absorb more and reflect less</li> <li>A microprocessor calculates the strength of the reflection and gives it a binary value</li> </ul>
Signup and view all the answers

What are the uses of a digital camera?

<ul> <li>Integrated into all smartphones</li> <li>Can take professional photos</li> <li>Security and surveillance systems</li> </ul>
Signup and view all the answers

Why is a digital camera used?

<ul> <li>Instant photos, no development required</li> <li>Digital photos can be transmitted easily over WiFi</li> <li>Embedded software can be used to adjust photos</li> </ul>
Signup and view all the answers

How does a digital camera work?

<ul> <li>Light enters the camera and shines on a sensor made up of many pixels</li> <li>Each pixel measures light intensity</li> <li>A microprocessor converts this into digital data representing colour values</li> </ul>
Signup and view all the answers

How does a keyboard work?

<ul> <li>Each character on a keyboard has a corresponding character set value</li> <li>Key presses are converted into digital signals which the computer interprets</li> </ul>
Signup and view all the answers

How does an optical mouse work?

<ul> <li>Uses a red LED and a sensor to determine the movement of the mouse relative to the surface</li> <li>Microprocessor analyses both speed and movement, replicating it on screen</li> </ul>
Signup and view all the answers

What are the uses of a microphone?

<ul> <li>Music recording</li> <li>Dictation</li> <li>Security</li> </ul>
Signup and view all the answers

Why is a microphone used?

<ul> <li>To capture any real world sound</li> <li>Sound can then be modified</li> </ul>
Signup and view all the answers

How does a microphone work?

<ul> <li>Vibrations caused by sound waves cause a coil to move around a magnet</li> <li>This results in electromagnetic field changes</li> <li>Tiny changes converted by a microprocessor and ADC into digital data</li> </ul>
Signup and view all the answers

What are the uses of QR codes?

<ul> <li>Advertising products</li> <li>Quick links to websites</li> <li>Electronic travel passes</li> </ul>
Signup and view all the answers

Why are QR codes used?

<p>Holds far more information than a traditional barcode.</p>
Signup and view all the answers

How do QR codes work?

<ul> <li>Read using a scanner (typically a phone)</li> <li>An app processes the image and converts the squares into readable data</li> </ul>
Signup and view all the answers

What are the three different types of touchscreen?

<ul> <li>Capacitive</li> <li>Infra-red</li> <li>Resistive</li> </ul>
Signup and view all the answers

How do capacitive touch screens work?

<ul> <li>Composed of a protective layer, transparent conductive layer and a glass substrate</li> <li>Touching the screen with a bare hand changes the electrostatic field of the transparent layer</li> </ul>
Signup and view all the answers

Where are capacitive touch screens used?

<ul> <li>Tablets</li> <li>Laptops</li> <li>Smartphones</li> </ul>
Signup and view all the answers

What are the advantages of capacitive touch screens?

<p>Excellent image quality, High precision, Durable screen that allows multiple touches at the same time.</p>
Signup and view all the answers

What is the disadvantage of capacitive touch screens?

<p>Requires a finger or stylus to activate.</p>
Signup and view all the answers

How do infra-red touch screens work?

<ul> <li>LEDs shine infra-red light across a screen, forming a matrix</li> <li>When the screen is touched, the matrix is broken</li> </ul>
Signup and view all the answers

Where are infra-red touch screens used?

<ul> <li>Large scale commercial displays</li> <li>Large information kiosks</li> <li>Medical equipment</li> </ul>
Signup and view all the answers

What are the advantages of infra-red touch screens?

<p>Excellent image quality, Unlimited touch life, Scales very well.</p>
Signup and view all the answers

What is the disadvantage of infra-red touch screens?

<p>Sensitive to interference from ambient light, water, snow etc.</p>
Signup and view all the answers

How do resistive touch screens work?

<ul> <li>Consists of two conductive layers</li> <li>Top layer is made of a flexible polyester material</li> <li>The two layers are separated by a insulator material</li> <li>When the screen is pressed the two layers connect and complete a circuit</li> </ul>
Signup and view all the answers

Where are resistive touch screens used?

<ul> <li>Cash machines</li> <li>Information kiosks</li> <li>Medical equipment</li> </ul>
Signup and view all the answers

What are the advantages of resistive touch screens?

<p>Cheap to produce, Can be activated using any object, Very resistant to surface contaminents.</p>
Signup and view all the answers

What is the disadvantage of resistive touch screens?

<p>Lower image clarity and precision compared to other types.</p>
Signup and view all the answers

What are the uses of 2D scanners?

<ul> <li>Creating digital versions of documents and photos</li> <li>Reading passports at airports</li> </ul>
Signup and view all the answers

What are the uses of 3D scanners?

<ul> <li>Creating 3D models with CAD software</li> <li>Dentistry</li> </ul>
Signup and view all the answers

Why are scanners used?

<p>Simple, cheap and effective way of generating digital representations of objects.</p>
Signup and view all the answers

How do 2D scanners work?

<ul> <li>Shine a bright light onto across a document</li> <li>Measure the levels of reflected light and creates digital version of it</li> </ul>
Signup and view all the answers

How do 3D scanners work?

<ul> <li>Shine a laser over the surface of an object</li> <li>Records its geometry and creates a digital model of it</li> </ul>
Signup and view all the answers

What are actuators used for?

<ul> <li>Starting and stopping a pump</li> <li>Opening and closing an automatic door</li> <li>Turning a wheel</li> </ul>
Signup and view all the answers

What do actuators do?

<p>Carry out physical movement.</p>
Signup and view all the answers

What are DLP projectors used for?

<ul> <li>Projecting a computer output onto a wall etc</li> <li>Personal and professional settings</li> </ul>
Signup and view all the answers

How do DLP projectors work?

<ul> <li>Use many micro mirrors arranged in a matrix placed on a microchip within the projector</li> <li>White light is shone through a rotating colour filter to produce an image while an angled mirror changes colour intensity</li> </ul>
Signup and view all the answers

What are the advantages of DLPs over LCDs?

<ul> <li>Higher contrast ratios</li> <li>Smoother video</li> <li>Smaller, lighter and more portable</li> </ul>
Signup and view all the answers

What are LCD projectors used for?

<p>Same as DLP projectors: projecting a computer output onto a wall etc in personal and professional settings.</p>
Signup and view all the answers

How do LCD projectors work?

<ul> <li>Use 3 mirror filters to separate an image into 3 different wavelengths of colour (RGB)</li> <li>Images are passed through a prism and recombined</li> <li>Full colour image is passed through a lens and projected</li> </ul>
Signup and view all the answers

What are the advantages of LCDs over DLPs?

<ul> <li>Sharper image</li> <li>Better colour reproduction</li> <li>Typically less expensive</li> </ul>
Signup and view all the answers

What are inkjet printers used for?

<ul> <li>Small scale print jobs</li> <li>Cheaper and smaller, popular for personal use</li> <li>Excellent for printing out high quality photos</li> </ul>
Signup and view all the answers

How do inkjet printers work?

<p>Force tiny droplets of liquid ink through very fine nozzles onto a sheet of paper.</p>
Signup and view all the answers

What are laser printers used for?

<ul> <li>High quality, inexpensive printing</li> <li>Very fast and accurate for non-colour documents and images</li> <li>Lower running cost per page compared to inkjet printer</li> </ul>
Signup and view all the answers

How do laser printers work?

<ul> <li>Use toner cartridges, which contain powdered, charged ink</li> <li>Using a laser, mirror image of the printer page is drawn onto a drum by creating negatively charged areas</li> <li>Drum then picks up positively charged ink particles and bonds them to the paper using heat</li> </ul>
Signup and view all the answers

What are LCDs used for?

<ul> <li>TV's, monitors, laptops, mobile devices</li> <li>Gradually being phased out by LED and OLED</li> </ul>
Signup and view all the answers

How do LCDs work?

<ul> <li>Made up of many tiny liquid crystals</li> <li>Crystals form a matrix of pixels which can be affected by changes in applied electrical fields</li> <li>LCDs require some form of backlighting</li> </ul>
Signup and view all the answers

What are LED displays used for?

<ul> <li>Replacing LCDs in more and more situations</li> <li>Multiple screens can be joined together, ideal for very large displays e.g. concerts, sporting events, festivals</li> </ul>
Signup and view all the answers

How do LED displays work?

<p>Uses tiny LEDs to produce a bright image almost instantly.</p>
Signup and view all the answers

Why are LED displays often considered better than traditional LCDs (with CCFL backlights)?

<ul> <li>Offer better image quality and viewing angles</li> <li>Has a longer lifespan</li> <li>Requires no additional backlighting so thinner and lighter</li> </ul>
Signup and view all the answers

How do speakers work?

<ul> <li>Digital representation of sound passes through DAC</li> <li>Further boosted by amplifier</li> <li>Passed to a speaker to create analogue sound waves</li> </ul>
Signup and view all the answers

What are 3D printers used for?

<ul> <li>Rapid prototyping</li> <li>Spare parts</li> <li>Inexpensive prosthetics</li> </ul>
Signup and view all the answers

How do 3D printers work?

<p>Deposit layers of material on top of each other to slowly build a 3D project.</p>
Signup and view all the answers

What are sensors?

<p>Input devices that measure physical properties in the environment and convert these measurements into digital data.</p>
Signup and view all the answers

What device converts an analogue signal to a digital signal?

<p>An analogue to digital converter (ADC).</p>
Signup and view all the answers

What device converts a digital signal to an analogue signal?

<p>A digital to analogue converter (DAC).</p>
Signup and view all the answers

What are the types of primary storage?

<ul> <li>RAM</li> <li>ROM</li> <li>Registers</li> <li>Cache</li> </ul>
Signup and view all the answers

What does secondary storage do?

<p>Stores data, programs and OS for future use.</p>
Signup and view all the answers

What are types of secondary storage?

<ul> <li>Optical storage</li> <li>Magnetic storage</li> <li>Solid state storage</li> </ul>
Signup and view all the answers

What are the features of primary storage?

<ul> <li>Volatile (mostly), lose all data held when the power is switched off</li> <li>Relatively small storage capacity when compared to secondary storage</li> <li>Physically close to the CPU, faster access speed</li> </ul>
Signup and view all the answers

What are the features of secondary storage?

<ul> <li>Non-volatile, retain data even when there is no power</li> <li>Have much greater storage capacity compared to primary storage</li> <li>Physically farther away from the CPU, slower access speed</li> </ul>
Signup and view all the answers

What is the ROM and its function?

<ul> <li>Small piece of read-only memory located on the motherboard</li> <li>Only primary storage that is non-volatile</li> <li>Contains startup instructions for the computer e.g. loading basic input/output system and checking hardware is installed correctly</li> <li>These instructions are called firmware</li> </ul>
Signup and view all the answers

What is the RAM and its function?

<ul> <li>Temporary read/write storage device close to the CPU that has very fast access speeds</li> <li>Stores instructions and data that are currently being processed by the CPU</li> <li>Holds the OS when the computer is running</li> <li>Volatile</li> </ul>
Signup and view all the answers

What are examples of things stored in the RAM for access by the CPU?

<ul> <li>The OS</li> <li>Programs that are running e.g. web browser, games</li> <li>Data currently in use e.g. data being downloaded/buffered</li> </ul>
Signup and view all the answers

What are the uses of secondary storage?

<ul> <li>Stores programs and data that are not currently in use or when the computer is turned off e.g. the OS</li> <li>Backing up or archiving data</li> </ul>
Signup and view all the answers

What are examples of optical storage?

<ul> <li>CDs</li> <li>DVDs</li> <li>Blu-ray discs</li> </ul>
Signup and view all the answers

How does optical storage work?

<ul> <li>Shines a laser on the disc and processes the reflection</li> <li>Uses pits and lands that are physically burnt onto the disc to represent 1s and 0s</li> </ul>
Signup and view all the answers

What are the advantages of optical storage?

<ul> <li>Cheap</li> <li>Lightweight</li> <li>Portable</li> </ul>
Signup and view all the answers

Flashcards

What is the role of the CPU?

To process data and instructions by carrying out a fetch-decode-execute cycle

What is a microprocessor?

A microchip installed on an integrated circuit that processes instructions

What does the von Neumann architecture consist of?

  • Control unit (CU)
  • Arithmetic logical unit (ALU)
  • Main memory (RAM)
  • Inputs and outputs

What is the von Neumann architecture based on?

Based on the stored program concept

Signup and view all the flashcards

What in the von Neumann architecture is stored in the same memory in binary form?

Instruction data and program data

Signup and view all the flashcards

What registers does the von Neumann architecture consist of?

  • Program counter (PC)
  • Memory address register (MAR)
  • Memory data register (MDR)
  • Accumulator
Signup and view all the flashcards

What is the role of the CU?

Decodes instructions using an instruction set and sends control signals to manage the flow of data and instructions within the CPU

Signup and view all the flashcards

What is the role of the ALU?

Performs operations and logical decisions on data

Signup and view all the flashcards

What is the role of the PC?

Holds the address of the next instruction to be fetched from memory

Signup and view all the flashcards

What is the role of the MAR?

Holds the memory address of the data that is to be fetched from or written to

Signup and view all the flashcards

What is the role of the MDR?

Holds the data that has been fetched from memory, or is about to be written to memory

Signup and view all the flashcards

What is the role of the ACC?

A register built into the ALU that stores the interim values of calculations

Signup and view all the flashcards

What is the role of the CIR?

Holds the current instruction to be decoded and executed

Signup and view all the flashcards

What is the role of the address bus?

Carries the addrresses of data that that needs to be read from or written to

Signup and view all the flashcards

What is the role of the data bus?

Carries the actual data or instructions

Signup and view all the flashcards

What is the role of the control bus?

Carries control signals transmitted by the CU to the other components

Signup and view all the flashcards

What are the steps of the fetch stage?

  1. PC points to the address of the next instruction to be fetched
  2. The address in the PC is copied to the MAR
  3. The MAR sends the address to the RAM via the address bus
  4. The data stored in the memory are copied into the MDR via the data bus
  5. The data stored in the MDR is copied into the CIR
  6. The PC increments by 1
Signup and view all the flashcards

What occurs in the decode stage?

The instructions in the CIR are decoded by the CU using an instruction set

Signup and view all the flashcards

What occurs in the execute stage?

  • The instruction is carried out e.g. performing a calculation
  • Depending on the instruction, data may end up being copied into the ALU and/or ACC
Signup and view all the flashcards

What is clock speed?

The number of fetch-decode-execute cycles the CPU can perform per second

Signup and view all the flashcards

What is clock speed controlled by?

The CPU's internal clock, synchronises operations

Signup and view all the flashcards

How does clock speed affect CPU performance?

The higher the clock speed, the greater the number of instructions that can be carried out per second, increasing performance

Signup and view all the flashcards

What is the cache?

The cache is very fast to access, volatile memory in the CPU that stores frequently used instructions and data

Signup and view all the flashcards

How does larger cache size affect performance?

Reduces the need to fetch instructions and data from memory, if more instructions can be stored more time can be saved, increasing performance

Signup and view all the flashcards

What is a core?

A complete copy of a CPU, with all the components

Signup and view all the flashcards

How does number of cores affect performance?

  • The more cores a computer has, the more multitasking a computer can do, increasing performance
  • Cores need to communicate with each other, taking time and decreasing performance
Signup and view all the flashcards

What code can a CPU ecexute?

Machine code (binary)

Signup and view all the flashcards

What is an instruction set?

Specific binary instructions that a CPU can understand and decode

Signup and view all the flashcards

What is a property of machine code?

Machine code produced for one computer won't work with another, it is machine specific

Signup and view all the flashcards

What is assembly language?

Mnemonics used to represent machine code and make it easier to understand e.g. LDA

Signup and view all the flashcards

What is an embedded system?

A computer system constructed within a device that carries out a specific task

Signup and view all the flashcards

What are properties of an embedded system?

  • Low power consumption
  • Small size
  • Low cost per unit
Signup and view all the flashcards

What are examples of embedded systems?

  • Dishwashers
  • Microwaves
  • Traffic lights
Signup and view all the flashcards

What are the uses of a barcode scanner?

  • Scanning goods at a supermarket checkout
  • Tracking packages out for delivery
Signup and view all the flashcards

Why is a barcode scanner used?

  • For faster checkouts
  • Reduces human error
Signup and view all the flashcards

How does a barcode scanner work?

  • Laser is shined on a barcode made of black and white lines of different thickness
  • White lines reflect light while black lines absorb more and reflect less
  • A microprocessor calculates the strength of the reflection and gives it a binary value
Signup and view all the flashcards

What are the uses of a digital camera?

  • Integrated into all smartphones
  • Can take professional photos
  • Security and surveillance systems
Signup and view all the flashcards

Why is a digital camera used?

  • Instant photos, no development required
  • Digital phots can be transmitted easily over WiFi
  • Embedded software can be used to adjust photos
Signup and view all the flashcards

How does a digital camera work?

  • Light enters the camera and shines on a sensor made up of many pixels
  • Each pixel measures light intensity
  • A microprocessor coverts this into digital data representing colour values
Signup and view all the flashcards

How does a keyboard work?

  • Each character on a keyboard has a corresponding character set value
  • Key presses are converted into digital signals which the computer interprets
Signup and view all the flashcards

How does an optical mouse work?

  • Uses a red LED and a sensor to determine the movement of the mouse relative to the surface
  • Microprocessor analyses both speed and movement, replicating it on screen
Signup and view all the flashcards

What are the uses of a microphone?

  • Music recording
  • Dictation
  • Security
Signup and view all the flashcards

Why is a microphone used?

  • To capture any real world sound
  • Sound can then be modified
Signup and view all the flashcards

How does a microphone work?

  • Vibrations caused by sound waves cause a coil to move around a magnet
  • This results in electromagnetic field changes
  • Tiny changes converted by a microprocessor and ADC into digital data
Signup and view all the flashcards

What are the uses of QR codes?

  • Advertising products
  • Quick links to websites
  • Electronic travel passes
Signup and view all the flashcards

Why are QR codes used?

Holds far more information than a traditional barcode

Signup and view all the flashcards

How do QR codes work?

  • Read using a scanner (typically a phone)
  • An app processes the image and converts the squares into readable data
Signup and view all the flashcards

What are the three different types of touchscreen?

  • Capacitive
  • Infra-red
  • Resistive
Signup and view all the flashcards

How do capacitive touch screens work?

  • Composed of a protective layer, transparent conductive layer and a glass substrate
  • Touching the screen with a bare hand changes the electrostatic field of the transparent layer
Signup and view all the flashcards

Where are capacitive touch screens used?

  • Tablets
  • Laptops
  • Smartphones
Signup and view all the flashcards

What are the advantages of capacitive touch screens?

  • Excellent image quality
  • High precision
  • Durable screen that allows multiple touches at the same time
Signup and view all the flashcards

What is the disadvantage of capacitive touch screens?

Requires a finger or stylus to activate

Signup and view all the flashcards

How do infra-red touch screens work?

  • LEDs shine infra-red light across a screen, forming a matrix
  • When the screen is touched, the matrix is broken
Signup and view all the flashcards

Where are infra-red touch screens used?

  • Large scale commercial displays
  • Large information kiosks
  • Medical equipment
Signup and view all the flashcards

What are the advantages of infra-red touch screens?

  • Excellent image quality
  • Unlimited touch life
  • Scales very well
Signup and view all the flashcards

What is the disadvantage of infra-red touch screens?

Sensitive to interference from ambient light, water, snow etc

Signup and view all the flashcards

How resistive touch screens work?

  • Consists of two conductive layers
  • Top layer is made of a flexible polyester material
  • The two layers are separated by a insulator material
  • When the screen is pressed the two layers connect and complete a circuit
Signup and view all the flashcards

Where are resistive touch screens used?

  • Cash machines
  • Information kiosks
  • Medical equipment
Signup and view all the flashcards

What are the advantages of resistive touch screens?

  • Cheap to produce
  • Can be activated using any object
  • Very resistant to surface contaminents
Signup and view all the flashcards

What is the disadvantage of resistive touch screens?

Lower image clarity and precision compared to other types

Signup and view all the flashcards

What are the uses of 2D scanners?

  • Creating digital versions of documents and photos
  • Reading passports at airports
Signup and view all the flashcards

What are the uses of 3D scanners?

  • Creating 3D models with CAD software
  • Dentistry
Signup and view all the flashcards

Why are scanners used?

Simple, cheap and effective way of generating digital representations of objects

Signup and view all the flashcards

How do 2D scanners work?

  • Shine a bright light onto across a document
  • Measure the levels of reflected light and creates digital version of it
Signup and view all the flashcards

How do 3D scanners work?

  • Shine a laser over the surface of an object
  • Records its geometry and creates a digital model of it
Signup and view all the flashcards

What are actuators used for?

  • Starting and stopping a pump
  • Opening and closing an automatic door
  • Turning a wheel
Signup and view all the flashcards

What do actuators do?

Carry out physical movement

Signup and view all the flashcards

What are DLP projectors used for?

  • Projecting a computer output onto a wall etc
  • Personal and professional settings
Signup and view all the flashcards

What do DLPs do?

  • Use many micro mirrors arranged in a matrix placed on a microchip within the projector
  • White light is shone through a rotating colour filter to produce an image while an angled mirror changes colour intensity
Signup and view all the flashcards

What are the advantages of DLPs over LCDs

  • Higher contrast ratios
  • Smoother video
  • Smaller, lighter and more portable
Signup and view all the flashcards

What are LCD projectors used for?

Same as DLP projectors

Signup and view all the flashcards

What do LCD projectors do?

  • Use 3 mirror filters to separate an image into 3 different wavelengths of colour (RGB)
  • Images are passed through a prism and recombined
  • Full colour image is passed through a lens and projected
Signup and view all the flashcards

What are the advantages of LCDs over DLPs

  • Sharper image
  • Better colour reproduction
  • Typically less expensive
Signup and view all the flashcards

What are inkjet printers used for?

  • Small scale print jobs
  • Cheaper and smaller, popular for personal use
  • Excellent for printing out high quality photos
Signup and view all the flashcards

What do inkject printers do?

Force tiny droplets of liquid link through very fine nozzles onto a sheet of paper

Signup and view all the flashcards

What are laser printers used for?

  • High quality, inexpensive printing
  • Very fast and accurate for non-colour documents and images
  • Lower running cost per page compared to inkjet printer
Signup and view all the flashcards

What do laser printers do?

  • Use toner cartridges, which contain powdered, charged ink
  • Using a laser, mirror image of the printer page is drawn onto a drum by creating negatively charged areas
  • Drum then picks up positively charged ink particles and bonds them to the paper using heat
Signup and view all the flashcards

What are LCDs used for?

  • TV's, monitors, laptops, mobile devices
  • Gradually being phased out by LED and OLED
Signup and view all the flashcards

What do LCDs do?

  • Made up of many tiny liquid crystals
  • Crystals form a matrix of pixels which can be affected by changes in applied electrical fields
  • LCDs require some form of backlighting
Signup and view all the flashcards

What are LED displays used for?

  • Replacing LCDs in more and more situations
  • Multiple screens can be joined together, ideal for very large displays e.g. concerts, sporting events, festivals
Signup and view all the flashcards

What do LED displays do?

Uses tiny LEDs to produce a bright image almost instantly

Signup and view all the flashcards

Why are LED displays better than LCDs?

  • Offer better image quality and viewing angles
  • Has a longer lifespan
  • Requires no additional backlighting so thinner and lighter
Signup and view all the flashcards

What do speakers do?

  • Digital representation of sound passes through DAC
  • Further boosted by amplifier
  • Passed to a speaker to create analogue sound waves
Signup and view all the flashcards

What are 3D printers used for?

  • Rapid prototyping
  • Spare parts
  • Inexpensive prosthetics
Signup and view all the flashcards

What do 3D printers do?

Deposit layers of material on top of each other to slowly build a 3D project

Signup and view all the flashcards

What are sensors?

Input devices that measure physical properties in the environment and covert these measurements into digital data

Signup and view all the flashcards

What device converts an analogue signal to a digital signal?

An analogue to digital converter (ADC)

Signup and view all the flashcards

What device converts a digital signal to an analogue signal?

A digital to analogue converter (DAC)

Signup and view all the flashcards

What are the types of primary storage?

  • RAM
  • ROM
  • Registers
  • Cache
Signup and view all the flashcards

What does secondary storage do?

Stores data, programs and OS for future use

Signup and view all the flashcards

What are types of secondary storage?

  • Optical storage
  • Magnetic storage
  • Solid state storage
Signup and view all the flashcards

What are the features of primary storage?

  • Volatile, lose all data held when the power is switched off
  • Relatively small storage capacity when compared to secondary storage
  • Physically close to the CPU, faster access speed
Signup and view all the flashcards

What are the features of secondary storage?

  • Non-volatile, retain data even when there is no power
  • Have much greater storage capacity compared to primary storage
  • Physically farther away from the CPU, slower access speed
Signup and view all the flashcards

What is the ROM and its function?

  • Small piece of read-only memory located on the motherboard
  • Only primary storage that is non-volatile
  • Contains startup instructions for the computer e.g. loading basic input/output system and checking hardware is installed correctly
  • These instructions are called firmware
Signup and view all the flashcards

What is the RAM and its function?

  • Temporary read/write storage device close to the CPU that has very fast access speeds
  • Stores instructions and data that are currently being processed by the CPU
  • Holds the OS when the computer is running
  • Volatile
Signup and view all the flashcards

What are examples of things stored in the RAM for access by the CPU?

  • The OS
  • Programs that are running e.g. web browser, games
  • Data currently in use e.g. data being downloaded/buffered
Signup and view all the flashcards

What are the uses of secondary storage?

  • Stores programs and data that are not currently in use or when the computer is turned off e.g. the OS
  • Backing up or archiving data
Signup and view all the flashcards

What are examples of optical storage?

  • CDs
  • DVDs
  • Blu-ray discs
Signup and view all the flashcards

How does optical storage work?

  • Shines a laser on the disc and process the reflection
  • Uses pits and lands that are physically burnt onto the disc to represent 1s and 0s
Signup and view all the flashcards

What are the advantages of optical storage?

  • Cheap
  • Lightweight
  • Portable
Signup and view all the flashcards

Study Notes

  • These flashcards cover key hardware concepts for IGCSE CIE Computer Science.

CPU Role and Microprocessors

  • The CPU processes data and instructions through a fetch-decode-execute cycle.
  • A microprocessor is a microchip on an integrated circuit that processes instructions.

Von Neumann Architecture

  • The von Neumann architecture comprises the control unit (CU), arithmetic logical unit (ALU), main memory (RAM), and input/outputs.
  • It is based on the stored program concept.
  • Instruction and program data are stored in the same memory in binary form.
  • Registers include the program counter (PC), memory address register (MAR), memory data register (MDR), and accumulator (ACC).

Core Unit (CU) & Arithmetic Logic Unit (ALU)

  • The CU decodes instructions and sends control signals to manage the data flow within the CPU.
  • The ALU performs arithmetic operations and logical decisions on data.

Registers: PC, MAR, MDR, ACC, CIR

  • The PC holds the address of the next instruction to be fetched.
  • The MAR holds the memory address of data to be fetched from or written to.
  • The MDR holds data fetched from or to be written to memory.
  • The ACC stores interim calculation values within the ALU.
  • The CIR holds the current instruction being decoded and executed.

Buses: Address, Data, Control

  • The address bus carries addresses of data to be read from or written to.
  • The data bus carries actual data or instructions.
  • The control bus carries control signals from the CU to other components.

Fetch-Decode-Execute Cycle: Fetch Stage

  • PC points to the address of the next instruction.
  • The address from PC is copied to MAR.
  • MAR sends the address to RAM via the address bus.
  • Data from memory are copied into MDR via the data bus.
  • The data in MDR is copied into CIR.
  • PC is incremented by 1.

Fetch-Decode-Execute Cycle: Decode & Execute Stages

  • During decode, instructions in the CIR are decoded by the CU using an instruction set.
  • During execute, the instruction is carried out, potentially involving data being copied into the ALU and/or ACC.

CPU Performance Factors: Clock Speed

  • Clock speed is the number of fetch-decode-execute cycles a CPU can perform per second.
  • CPU's internal clock controls clock speed, synchronizing operations.
  • Higher clock speed increases performance by allowing more instructions to be carried out each second.

CPU Performance Factors: Cache and Cores

  • Cache is fast to access, volatile memory in the CPU for storing frequently used instructions and data.
  • Larger cache reduces the need to fetch from memory, improving performance.
  • A core is a complete copy of a CPU with all components.
  • More cores allow for more multitasking, increasing performance, but communication between cores can decrease performance.

Instruction Sets and Machine Code

  • CPUs execute machine code (binary).
  • An instruction set consists of specific binary instructions a CPU can understand and decode.
  • Machine code is machine-specific and not cross-compatible.

Assembly Language

  • Assembly language uses mnemonics to represent machine code for easier understanding (ex: LDA).

Embedded Systems

  • An embedded system is a computer system within a device performing a specific task.
  • Properties include low power consumption, small size, and low cost per unit.
  • Examples of embedded systems are dishwashers, microwaves, and traffic lights.

Barcode Scanners

  • Used for scanning goods at checkouts and tracking packages.
  • Usage benefits include faster checkouts and reduced human error.
  • The scanner shines a laser on a barcode, measures light reflection, and converts it to a binary value.

Digital Cameras

  • Uses include integration in smartphones, professional photography, and security systems.
  • Benefits are instant photos, easy transmission over WiFi, and embedded software for adjustments.
  • Light enters, shines on a pixel sensor, each pixel measures intensity, and a microprocessor converts this into digital data.

Keyboards and Optical Mice

  • Key presses on a keyboard are converted into digital signals based on character set values.
  • Optical mice use a red LED and sensor to track movement, which a microprocessor analyzes and replicates on-screen.

Microphones

  • Used for music recording, dictation, and security.
  • Captures real-world sound that can then be modified.
  • Sound waves cause coil movement around a magnet, leading to electromagnetic field changes, which are converted into digital data.

QR Codes

  • Used for advertising products, linking to websites, and electronic travel passes.
  • QRCodes hold more information than traditional barcodes.
  • A scanner/app processes the QR image and converts squares into readable data.

Touchscreens: Capacitive

  • Touchscreens include capacitive, infra-red, and resistive types.
  • Capacitive screens consist of protective, transparent conductive layer and glass substrate.
  • Touching the screen changes the electrostatic field.
  • Used in tablets, laptops, and smartphones.
  • Advantages are excellent image quality, high precision, and durability with multi-touch support.
  • Requires a finger or stylus to activate.

Touchscreens: Infra-red

  • Infra-red touchscreens use LEDs to shine infra-red light across a screen in a matrix.
  • Touching the screen breaks the matrix.
  • Used in large commercial displays, information kiosks, and medical equipment.
  • Advantages include excellent image quality, unlimited touch life, and scalability.
  • Sensitive to interference from ambient light, water, snow, etc.

Touchscreens: Resistive

  • Resistive touchscreens have two conductive layers separated by an insulator.
  • Pressure connects the layers, completing a circuit.
  • Used in cash machines, information kiosks, and medical equipment.
  • Advantages: cheap to produce, activated by any object, resistant to surface contaminants.
  • Lower image clarity and precision compared to the other types of touchscreens.

2D and 3D Scanners

  • 2D scanners are utilized for creating digital versions of documents and photos, and reading passports.
  • 3D scanners are utilized for creating 3D models with CAD software and in dentistry.
  • Scanners offer a simple, cheap, and effective tool for generating digital representations of objects.
  • 2D scanners shine a light across a document to measure reflected light and create a digital version.
  • 3D scanners shine a laser over the object's surface to record its geometry and create a digital model.

Actuators

  • Actuators are used for starting/stopping pumps, opening/closing doors, and turning wheels.
  • Carries out physical movement.

Projectors: DLP

  • DLP projectors project computer output onto a wall and are used personally and professionally.
  • DLPs use micro-mirrors on a microchip.
  • White light shone through a rotating color filter produces an image while an angled mirror changes color intensity.
  • Advantages over LCD projectors are higher contrast, smoother video, and being more portable.

Projectors: LCD

  • LCD projectors are used same as DLP projectors
  • LCD projectors uses 3 mirror filters to separate an image into 3 different wavelengths of colour (RGB)
  • Images are passed through a prism and recombined.
  • Full colour image is passed through a lens and projected.
  • Advantages over DLP projectors: sharper image, better colour reproduction, and are typically less expensive.

Printers: Inkjet

  • Inkjet printers are used for Small scale print jobs, personal use and high-quality photos.
  • Inkjet printers force tiny droplets of liquid ink through nozzles onto paper.

Printers: Laser

  • Laser printers are used for high-quality, inexpensive printing.
  • Very fast and accurate for non-colour documents and images
  • Offer a lower running cost per page compared to inkjets.
  • Laser printers use toner cartridges with powdered, charged ink.
  • A laser draws a mirror of the print page onto a drum negatively charged areas.
  • The drum picks up positively charged ink particles and bonds them to paper using heat.

Displays: LCD

  • LCDs are used in TV's, monitors, laptops, mobile devices.
  • Gradually being phased out by LED and OLED
  • Has tiny liquid crystals that form a matrix of pixels, which are affected by changes in applied electrical fields.
  • LCDs require backlighting.

Displays: LED

  • LED displays replace LCDs.
  • Multiple screens can be joined together, ideal for very large displays e.g. concerts, sporting events, festivals.
  • LED displays uses tiny LEDs to produce a bright image almost instantly.
  • Offer better image quality, viewing angles, longer lifespan, and are thinner/lighter than LCDs.

Speakers

  • Speakers create analogue sound waves
  • Digital representation of sound passes through DAC and boosted by amplifier and passed to a speaker.

3D Printers

  • Uses include rapid prototyping, spare parts, and inexpensive prosthetics.
  • Deposit layers of material on top of each other to slowly build a 3D project.

Sensors

  • Sensors are input devices that measure physical properties in the environment and covert these measurements into digital data.

Analogue to Digital Conversion and Digital to Analogue Conversion

  • An analogue to digital converter (ADC) converts an analogue signal to a digital signal.
  • A digital to analogue converter (DAC) converts a digital signal to an analogue signal.

Primary Storage

  • Primary storage includes RAM, ROM, registers, and cache.
  • Registers and Cache have extremely fast access speeds
  • Primary storage has volatile, data is lost when power is switched off.
  • Secondary storage stores data, programs and OS for future use

Secondary Storage

  • Secondary storage include optical, magnetic, and solid-state storage. Secondary storage has much greater storage capacity and relatively low access speeds

Primary Storage Features

  • Volatile; data is lost when power is switched off.
  • Relatively small storage capacity.
  • Physically close to the CPU, with faster access speeds.

Secondary Storage Features

  • Non-volatile, retains data even when there is no power.
  • Have much greater storage capacity compared to primary storage.
  • Physically farther away from the CPU, slower access speed.

ROM

  • ROM (read-only memory) is a small piece of non-volatile memory on the motherboard.
  • Contains startup instructions (firmware) such as loading the basic input/output system and hardware check.

RAM

  • RAM (random-access memory) is a temporary read/write storage device close to the CPU that has very fast access speeds
  • Stores instructions and data currently processed by the CPU, including the OS when running.
  • Volatile.

RAM Usage Examples

  • The OS
  • Programs that are running e.g. web browser, games
  • Data currently in use e.g. data being downloaded/buffered

Secondary Storage Usage

  • Stores programs and data when not in use or when the computer is turned off (ex: the OS).
  • Used for backing up or archiving data.

Optical Storage Examples

  • CDs
  • DVDs
  • Blu-ray discs

Optical Storage Function

  • Shines a laser on the disc and process the reflection
  • Uses pits and lands physically burnt onto the disc to represent 1s and 0s.

Optical Storage Advantages

  • Cheap
  • Lightweight
  • Portable

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Quiz Team

More Like This

Use Quizgecko on...
Open
Browser
Browser