Definition - What does Expansion Card mean?
An expansion card is an electronic card/board that is used to add extra functionality to a computer. It is inserted into an expansion slot on the motherboard of a computer. Expansion cards contain edge connectors that are used to create an electronic link between motherboard and card, thus enabling these two to communicate.
Many different classes of expansion card are available, including sound cards, video graphics cards, network cards and so on. All expansion cards are used to enhance the quality of their specific function. For example, video graphics cards are used to enhance the video quality on a computer.
Expansion cards are also known as add-on cards or interface cards.
Techopedia explains Expansion Card
The basic purpose of expansion cards is to enhance the existing abilities of the motherboard. The adoption of expansion cards occurred rapidly in the computing world because of the ability for users to customize performance.
The very first computer with expansion capabilities, the Altair-8800, was introduced in 1975. Following on Altair-8800's debut, Intel began manufacturing expansion slots on a large scale for use in the corporate sector. Intel launched their PCI slot as replacement for ISA in 1991. This was followed by the AGP bus in 1997. The AGP bus was designed specifically for video. In 2005, both PCI and AGP were replaced with PCI Express.
With the invention of USB, the computer have became more flexible in that devices can be added to augment performance without requiring the use of an expansion card. However, video cards, sound cards and are still used to customize PCs.