Category How does It works, How things work, How is it done, Curiosity

A Pixel is a tiny dot of color, which, together with millions of other dots, makes up a picture on a computer or television screen. It is short for “picture element”. A pixel is the smallest unit of a digital image or graphic that can be displayed and represented on a digital display device.

A pixel is the basic logical unit in digital graphics. Pixels are combined to form a complete image, video, text or any visible thing on a computer display. A pixel is also known as a picture element.

A pixel is represented by a dot or square on a computer monitor display screen. Pixels are the basic building blocks of a digital image or display and are created using geometric coordinates. Depending on the graphics card and display monitor, the quantity, size and color combination of pixels varies and is measured in terms of the display resolution.

For example, a computer with a display resolution of 1280 x 768 will produce a maximum of 98,3040 pixels on a display screen. Each pixel has a unique logical address, a size of eight bits or more and, in most high-end display devices, the ability to project millions of different colors.

The pixel resolution spread also determines the quality of display; more pixels per inch of monitor screen yields better image results.

 

Inside the processing unit of a computer are collections of integrated circuits (microchips) and other components, usually positioned on circuit boards. There are also slots for floppy disks and CDs to be inserted, a “hard disk” on which data is stored, and perhaps devices such as fans to keep the components cool. Portable computers also have space for a battery, which can be recharged.

It is imperative to understand the name and function of each component in a computer in order to understand how it functions as a whole. Attempt to always remember that a computer is based off the human body and functions in the same way. You cannot expect to understand the human body without first understanding its organs and their functions. A computer is composed of components in the same way that the body is composed of organs that together work to make the body or computer function. A basic computer has at least 8 basic components which include a computer case or tower, motherboard, Central Processing Unit (CPU), Power Supply Unit (PSU), Random Access Memory (RAM), hard drive (HDD), Graphic Processing Unit (GPU) and some type of optical drive which would be your CD/DVD drive. These 7 components are the backbone of every healthy, functioning computer.

Motherboards

Motherboards often referred to as a logic board, main board or “mobo” for short, are the “back-bone” of the computer. Its purpose is to connect all the parts of the computer together and make everything centralized using its printed circuit board. The central processing unit, hard drives, memory, graphic processing unit, printers, and other ports all connect to the computer directly or via special cables that attach on to the motherboard. When you plug in a USB or thumb drive to a computer you are actually plugging it directly into the computer!

Power Supply

True to its name, the power supply powers all other components of the machine. It usually plugs into the motherboard to power the other parts. The power supply connects to either an internal battery (on a laptop) or a plug for an outlet (on a desktop).

Central Processing Unit (CPU)

A CPU, sometimes referred to as a computer’s brain, is the workhorse of the machine. It performs the calculations needed by a system, and can vary in speed. The work that a CPU does generates heat, which is why your computer has a fan inside. A more powerful CPU is necessary for intense computer work like editing high-definition video or programming complex software.

Random-access Memory (RAM)

RAM is temporary memory. Whenever you open up a Microsoft Word window, your computer places it in RAM, and when you close the window, that RAM is freed. Since RAM is volatile, its contents are lost if the machine loses power. This is why you lose a Word document when the power goes out if you didn’t save it.

Hard Disk Drive / Solid State Drive

Since RAM is temporary, your computer needs a place to store data permanently. That’s where the hard drive comes in. The traditional hard drive consists of several spinning platters with an arm that physically writes data to the disk. However, these drives are slow and are starting to be replaced by the faster solid-state drives.

Video Card

A video card is a dedicated unit for handling the output of images to a display. Video cards have their own dedicated RAM for performing these functions. A high-end video card is required to process extremely intense visual functions, such as computer drafting by engineers. Like many components, many types of video cards are available with varying power and prices.

Optical Drives

Though less common than they used to be, many machines still have an optical drive for reading CDs and DVDs. These can be used to listen to music or watch movies, place information onto a blank disc, or install software from a disc. Since most software nowadays is installed from the internet instead of using discs, these aren’t as important as they once were, especially on laptops.

Input and Output Devices

Depending on your particular computer, you can connect a variety of devices to send information into it or out of it. Common input devices include mice (touchpads on laptops), keyboards, and webcams, while output devices consist of monitors, printers, and speakers. Removable media such as flash drives and SD cards can also be used to transfer data between computers.

An optical mouse is technologically much more advanced than a mechanical mouse. Unlike the latter, an optical mouse is completely electronic and therefore has no moving parts. It consists of an LED (that generates the signature red light), a light-detector chip, a switch mechanism and a few other simple components. Some mice have another LED that lights up a plastic strip installed at the back of the mouse as an indication of the mouse’s operation.

The LED installed at the bottom of the mouse emits a bright light in the downward direction. Since a mouse is usually used on plain surfaces, the light bounces back from the surface and enters a photocell that’s also mounted on the bottom, almost next to the LED. This photocell has a frontal lens that magnifies any light reaching it. As you move the mouse around, the pattern of the reflected beam changes; this is then used by the light-detector chip to figure out how and in which direction you’re moving the mouse.

Some optical mice have two LEDs. The first one shines light down onto the desk. The light from that is picked up by the photocell. The second LED lights up a red plastic strip along the back of the mouse so you can see it’s working. Most optical mice also have a wheel at the front so you can scroll pages on-screen much faster. You can click the wheel too, so it functions like the third (center) button on a conventional ball mouse.

Optical mice are much lighter and faster than mechanical ones, and have therefore gained enormous popularity all over the world. With improvements in technology, newer and even more advanced mice – that address issues like ergonomics and the health of the user – are taking center stage. The choice of the right variant rests with the user, but one thing remains universally true – computers and mice shall always remain inseparable.

A Mouse is a device for giving the computer information (an input device). When the mouse is pushed around on a mat, a pointer on the computer’s screen is moved, indicating how data needs to be changed, moved or processed. Tiny beams of light inside the mouse shine through slotted wheels. The ball of the mouse moves as it is pushed across the mat, and the beams of light are interrupted in a way that tells the computer the direction that the mouse is moving.

A mouse is something you push along your desktop to make a cursor (pointing device) move on your screen. So what a mouse has to do is figure out how much you’re moving your hand and in which direction. There are two main kinds of mice and they do this job in two different ways, either using a rolling rubber ball (in a ball-type mouse) or by bouncing a light off your desk (in an optical mouse).

How does a mouse like this actually work? As you move it across your desk, the ball rolls under its own weight and pushes against two plastic rollers linked to thin wheels. One of the wheels detects movements in an up-and-down direction (like the y-axis on graph/chart paper); the other detects side-to-side movements (like the x-axis on graph paper).

How do the wheels measure your hand movements? As you move the mouse, the ball moves the rollers that turn one or both of the wheels. If you move the mouse straight up, only the y-axis wheel turns; if you move to the right, only the x-axis wheel turns. And if you move the mouse at an angle, the ball turns both wheels at once. Now here’s the clever bit. Each wheel is made up of plastic spokes and, as it turns, the spokes repeatedly break a light beam. The more the wheel turns, the more times the beam is broken. So counting the number of times the beam is broken is a way of precisely measuring how far the wheel has turned and how far you’ve pushed the mouse. The counting and measuring is done by the microchip inside the mouse, which sends details down the cable to your computer. Software in your computer moves the cursor on your screen by a corresponding amount.

There are various problems with mice like this. They don’t work on all surfaces. Ideally, you need a special mouse mat but, even if you have one, the rubber ball and its rollers gradually pick up dirt, so the x- and y-axis wheels turn erratically and make the pointer stutter across your screen. One solution is to keep taking your mouse to pieces and cleaning it; another option is to get yourself an optical mouse.

Traditional mice have a rubber ball inside them. Open one up and you can see the heavy ball clearly and the spring that keeps it in position.

(1) Switch detects clicks of left mouse button. (2) Switch for middle button. (3) Switch for right button. (4) Old-style connection to PS/2 socket on computer. (5) Chip turns back-and-forth (analog) mouse movements into numeric (digital) signals computer can understand. (6) X-axis wheel turns when you move mouse left and right. (7) Y-axis wheel turns when you move mouse up and down. (8) Heavy rubber wheel. (9) Spring presses rubber ball firmly against X- and Y-axis wheels so they register movements properly. (10) Electrolytic capacitor (11) Resistors. (See picture):

Inside a computer is a “hard disk”, which is able to store information (data) even when the machine is turned off. There are also two other kinds of storage in a computer. ROM (read-only memory) stores the instructions that tell the computer how to start working when it is first switched on. RAM (random-access memory) stores data that is in use. To make sure that data is permanently stored, it must be “saved” on the hard disk before the computer is switched off.

At the core of the computer is the central processing unit or CPU, the source of control that runs all programs and instructions. In order to function, computers use two types of memory: primary and secondary. The main storage is the primary memory, and data and programs are stored in secondary memory.

Data is stored as lots of binary numbers, by magnetism, electronics or optics. … The computer’s operating system, for example, contains instructions for organizing data into files and folders, managing temporary data storage, and sending data to application programs and devices such as printers.

Magnetic storage is commonly used on the hard disc drives found on most computers. Information is stored using positive and negative magnetic charges to correspond with the 1s and 0s noted above. Optical discs like CDs and DVDs store information as binary code that can be read by an optical sensor in a disc drive.