An expansion card can also be referred to as an expansion board, adaptor card or occasionally an accessory card. Their purpose is to increase the functionality of a computer, for example adding a wireless card will allow your computer to connect to a wireless network. Usually, for brevity, we simply refer to an expansion card by its purpose eg wireless card, modem, network card.

There are several different expansion slot types some of which have dedicated purposes such as an AGP slot and others which can have a wide variety of cards installed into it such as a PCI slot. PCI express X16 and the older AGP slots are predominately used for graphics cards. PCI, PCI express x1 and the venerable ISA slot can be used for many different types of expansion cards, with PCI having the best range of choices at the time of writing. PCI is slowly being superseded by PCI express x1 and ISA is completely obsolete and rarely available except on specialty industrial motherboards. The mainboard section of this site shows examples of expansion slots. Some commonly encountered expansion slots are -

• PCI Express X16
• PCI Express X1
• AGP
• PCI
• ISA
• Compact Flash
• Cardbus/PC Card/PCMCIA

There are many different types of expansion cards that provide your computer the ability to perform many different and varied tasks. Some commonly encountered cards are -

• Graphics Cards
• Sound Cards
• Network Cards
• Wireless Cards
• Internal Modems
• TV Tuner Cards
• SCSI Controllers
• Raid Controllers
• IDE/SATA Controllers
• Interface Adaptors (Eg USB, parallel and serial ports etc)
• Security Devices

As with all of your PC purchases if you have doubts about the suitability or compatibility of a particular expansion card you should consult your hardware vendor. They will be most happy to guide you particularly if it leads to a sale, so dont be afraid to ask them what is required to achieve your goals.