- The central processing unit, or CPU, is that part of a computer which executes software program instructions.
- The microprocessor often plugs into the motherboard using one of many different types of sockets.
- The central processing unit carries out each instruction of the program in sequence, to perform the basic arithmetical, logical, and input/output operations of the system
- The IC has allowed increasingly complex CPUs to be designed and manufactured to tolerances on the order of nanometers.
- IBM PC compatible computers use an x86-compatible processor, usually made by Intel, AMD, VIA Technologies or Transmeta.
- Apple Macintosh computers were initially built with the Motorola 680x0 family of processors, then switched to the PowerPC series
- In older computers circuitry was formerly on several printed circuit boards, but in PCs is a single integrated circuit
- CPUs for a particular application has largely given way to the development of mass-produced processors that are made for one or many purposes.
- CPUs have increased the presence of these digital devices in modern life far beyond the limited application of dedicated computing machines.
- A computer case is also known as a computer chassis, cabinet, box, tower, enclosure, housing, system unit or simply case which is the enclosure that contains most of the components of a computer
- Cases are usually constructed from steel (often SECC—Steel, Electrically Chromate Coated) or aluminium. Plastic is sometimes used.
- The size and shape of a computer case is usually determined by the form factor of the motherboard, since it is the largest component of most computers
- Computer cases usually include sheet metal enclosures for a power supply unit and drive bays, as well as a rear panel that can accommodate peripheral connectors protruding from the motherboard and expansion slots.
- Some computer cases include a biased switch (push-button) which connects to the motherboard.
- The motherboard is usually screwed to the case along its largest face, which could be the bottom or the side of the case depending on the form factor and orientation.
- Companies like In Win Development, Shuttle Inc. and AOpen have popularized small cases, for which FlexATX is the most common motherboard size
- Tower cases have either a single side panel which may be removed in order to access the internal components or a large cover that saddles the chassis.
- Case modding is the artistic styling of computer cases, often to draw attention to the use of advanced or unusual components.
- Modded cases may also include internal lighting, custom paint, or liquid cooling systems. Some hobbyists build custom cases from raw materials like aluminum, steel, styrofoam, acrylic, or wood.
- A Mouse on a computer is a small, slide able device that users hold and slide around to point at, click on, and sometimes drag objects on screen in a graphical user interface using a pointer on screen.
- It sometimes features other elements, such as "wheels", which allow the user to perform various system-dependent operations, or extra buttons or features that can add more control or dimensional input.
- The ball-mouse replaced the external wheels with a single ball that could rotate in any direction. It came as part of the hardware package of the Xerox Alto computer
- The ball mouse has two freely rotating rollers. They are located 90 degrees apart. One roller detects the forward–backward motion of the mouse and other the left–right motion
- Mice traditionally detected movement and communicated with the computer with an internal "mouse ball"; and used optical encoders to detect rotation of the ball and tell the computer where the mouse has moved
- Modern computer mice took form at the Colet poly technique Laurianne (EPFL) under the inspiration of Professor Jean-Daniel Nicole and at the hands of engineer and watchmaker Andre Guardian
- An optical mouse uses a light-emitting diode and photo diodes to detect movement relative to the underlying surface, rather than internal moving parts as does a mechanical mouse.
- A mouse-related controller called the Space Ball has a ball placed above the work surface that can easily be gripped.
- Standard PC mice once used the RS-232C serial port via a D-subminiature connector, which provided power to run the mouse's circuits as well as data on mouse movements.
- A mouse typically controls the motion of a cursor in two dimensions in a graphical user interface (GUI).
- In computing, a keyboard is a typewriter keyboard, which uses an arrangement of buttons or keys, to act as mechanical levers or electronic switches
- A keyboard typically has characters engraved or printed on the keys and each press of a key typically corresponds to a single written symbol.
- Keyboards are also used for computer gaming, either with regular keyboards or by using keyboards with special gaming features, which can expedite frequently used keystroke combinations.
- Standard "full-travel" alphanumeric keyboards have keys that are on three-quarter inch centers (0.750 inches, 19.05 mm), and have a key travel of at least 0.150 inches (3.81 mm).
- Keyboards on laptops and notebook computers usually have a shorter travel distance for the keystroke and a reduced set of keys. They may not have a numerical keypad, and the function keys may be placed in locations that differ from their placement on a standard, full-sized keyboard.
- Numeric keyboards contain only numbers, mathematical symbols for addition, subtraction, multiplication, and division, a decimal point, and several function keys
- Software keyboards or on-screen keyboards often take the form of computer programs that display an image of a keyboard on the screen. Another input device such as a mouse or a touchscreen can be used to operate each virtual key to enter text.
- Holdable (also called flexible) keyboards are made of soft plastic or silicone which can be rolled or folded on itself for travel.
- Programs use keyboard shortcuts very differently and all use different keyboard shortcuts for different program specific operations, such as refreshing a web page in a web browser or selecting all text in a word processor.
- These different keyboard layouts arise mainly because different people need easy access to different symbols, either because they are inputting text in different languages,
- A visual display unit (or monitor) is a piece of electrical equipment, usually separate from the computer case, which displays viewable images generated by a computer without producing a permanent record.
- The monitor comprises the display device, circuitry, and an enclosure. The display device in modern monitors is typically a thin film transistor liquid crystal display (TFT-LCD) thin panel,
- The size of an approximately rectangular display is usually given as the distance between two opposite screen corners, that is, the diagonal of the rectangle.
- Phosphor burn-in is localized aging of the phosphor layer of a CRT screen where it has displayed a static image for long periods of time. This results in a faint permanent image on the screen, even when turned off.
- The monitor comprises the display device, circuitry to generate a picture from electronic signals sent by the computer, and an enclosure or case.
- Burn-in re-emerged as an issue with early plasma displays, which are more vulnerable to this than CRTs. Screen savers with moving images may be used with these to minimize localized burn. Periodic change of the color scheme in use also helps.
- Early digital monitors are sometimes known as TTLs because the voltages on the red, green, and blue inputs are compatible with TTL logic chips. Later digital monitors support LVDS, or TMDS protocols.
- Green and amber phosphors were used on most monochrome displays in the 1970s and 1980s. White was uncommon because it was more expensive to manufacture, although Apple used it on the Lisa and early Macintoshes.
- Most modern computer displays can show the various colors of the RGB color space by changing red, green, and blue analog video signals in continuously variable intensities. These are almost exclusively progressive scan.
- Multiple devices can be connected to the same monitor using a video switch. In the case of computers, this usually takes the form of a "Keyboard Video Mouse switch" (KVM) switch, which is designed to switch all of the user interface devices for a workstation between different computers at once.
- The video card - otherwise called a graphics card, graphics adapter or video adapter - processes and renders the graphics output from the computer to the computer display
- Many video cards offer added functions, such as accelerated rendering of 3D scenes and 2D graphics, video capture, TV-tuner adapter, MPEG-2/MPEG-4 decoding, FireWire, light pen, TV output, or the ability to connect multiple monitors
- Video hardware can be integrated on the motherboard. However limitation to this integrated graphics chip often only occurs with early machines
- A dedicated Graphics Card on the other hand has its own RAM and Processor specifically for processing video images, and thus offloads this work from the CPU and system RAM
- he video BIOS or firmware contains the basic program, which is usually hidden, that governs the video card's operations and provides the instructions that allow the computer and software to interact with the card.
- The RAMDAC, or Random Access Memory Digital-to-Analog Converter, converts digital signals to analog signals for use by a computer display that uses analog inputs such as CRT displays
A GPU is a dedicated processor optimized for accelerating graphics.
- The processor is designed specifically to perform floating-point calculations, which are fundamental to 3D graphics rendering.
- Digital-based standard designed for displays such as flat-panel displays (LCDs, plasma screens, wide high-definition television displays) and video projectors.
- Video cards may use a lot of electricity, which is converted into heat. If the heat isn't dissipated, the video card could overheat and be damaged.
- An advanced digital audio/video interconnect released in 2003 and is commonly used to connect game consoles and DVD players to a display.
