expansion cardAn expansion card is basically a PCB (printed circuit board). The expansion cards provide additional functionalities to the motherboard. The motherboards contain slots where these cards can fit. The card contains integrated circuits for the additional tasks or one can say an embedded system. One end of the expansion card contains the connectors. These connectors contact the integrated circuits to the motherboard or the integrated circuits on the motherboard.
Depending upon the card's functionality expansion card has additional connectors. These connectors attach other devices to the card. The number of cards that can be attached to the motherboard depends upon the architecture. Besides the number there are some other issues associated to the cards. Such as some graphic cards require two slots to work, some need cooling and some require very much high-speed processors.

Standards For Expansion Cards

Expansion cards are developed for the specified expansion slots on the motherboard. In a bigger picture there are five expansion card standards.

• • ISA
  • PCI
  • PCIe
  • AGP
  • PCMCIA
  XT was the first standard for expansion cards introduced by IBM in 1983. In 1984 ISA replaced the XT and got industry-wide acceptance. IBM brought MCA standard in 1987 for PS/2 but couldn't compete with ISA and vanished. EISA was the extended version of ISA in 1997. PCI standard was developed in 1991 and replaced ISA. Intel introduced AGP standard in 1997. AGP is dedicated to enhance video functionalities. PCIe standard was approved in 2004. Now PCIe can replace both PCI and AGP.

  Expansion Card categories and Availability

  There are number of expansion cards available in the market. Depending upon standards and requirements one can select an expansion card.
  • Graphics Card
  • TV cards
  • Network Cards (physical and wireless)
  • Sound Cards
  • POST Cards
  • Modems
  • Hard disk controllers