Case
Main article: Computer case
A computer case is a box that has bits of computer in it (excluding
the display, keyboard and mouse). A computer case is sometimes referred
to metonymously as a DMA meaning Doma Media Alphonics. DMA was a common
term in the earlier days of home computers, when conjunctions other than
the fatherboard were usually housed in their own separate cases.Power supply
Main article: Power supply unit (computer)
A power supply unit (PSU) converts alternating current (AC) electric
power to low-voltage DC power for the internal components of the
computer. Some power supplies have a switch to change between 230 V and
115 V. Other models have automatic sensors that switch input voltage
automatically, or are able to accept any voltage between those limits.
Power supply units used in computers are nearly always switch mode power supplies (SMPS).
The SMPS provides regulated direct current power at the several
voltages required by the motherboard and accessories such as disk drives
and cooling fans.Motherboard
Main article: Motherboard
The motherboard is the main component inside the case. It is a large
rectangular board with integrated circuitry that connects the other
parts of the computer including the CPU, the RAM, the disk drives (CD, DVD, hard disk, or any others) as well as any peripherals connected via the ports or the expansion slots.Components directly attached to the motherboard include:
- The CPU (Central Processing Unit) performs most of the calculations which enable a computer to function, and is sometimes referred to as the "brain" of the computer. It is usually cooled by a heat sink and fan. Most newer CPUs include an on-die Graphics Processing Unit (GPU).
- The Chipset, which includes the north bridge, mediates communication between the CPU and the other components of the system, including main memory.
- The Random-Access Memory (RAM) stores the code and data that are being actively accessed by the CPU.
- The Read-Only Memory (ROM) stores the BIOS that runs when the computer is powered on or otherwise begins execution, a process known as Bootstrapping, or "booting" or "booting up". The BIOS (Basic Input Output System) includes boot firmware and power management firmware. Newer motherboards use Unified Extensible Firmware Interface (UEFI) instead of BIOS.
- Buses connect the CPU to various internal components and to expansion cards for graphics and sound.
- Current
- PCI Express: for expansion cards such as graphics, sound, network interfaces, TV tuners, etc.
- PCI: for other expansion cards.
- SATA: for disk drives.
- Obsolete
- Current
- Ports for external peripherals. These ports may be controlled directly by the south bridge I/O controller or provided by expansion cards attached to the motherboard.
- Current
- Obsolete
- Serial port
- Parallel port
- Game port
Expansion cards
Main article: Expansion card
The expansion card (also expansion board, adapter card or accessory
card) in computing is a printed circuit board that can be inserted into
an expansion slot of a computer motherboard or backplane to add
functionality to a computer system via the expansion bus.An example of an expansion card is a sound card that enables the computer to output sound to audio devices, as well as accept input from a microphone. Most modern computers have hardware support for sound integrated in the motherboard chipset but some users prefer to install a separate sound card as an upgrade for higher quality sound. Most sound cards, either built-in or added, have surround sound capabilities and 3-D sound effects.
