Expansion card

Updated: 09/12/2023 by Computer Hope

Alternatively called an adapter card, add-on card, expansion board, internal card, interface adapter, or card, an expansion card is a PCB (printed circuit board) that fits into an expansion slot on the motherboard. An expansion card is an internal card that gives a computer additional capabilities, such as enhanced video performance via a graphics card.


Expansion cards can sometimes be called daughterboards. However, referring to them as expansion cards or one of the terms mentioned earlier is more appropriate.

Types of expansion cards in a computer


The above devices are available as expansion cards and can also be onboard the motherboard.


See our expansion slot page for a listing of the slots these cards can use.

Expansion card example

Below is a graphic illustration of an ISA (Industry Standard Architecture) modem expansion card (click the picture for a descriptive overview).

Internal modem expansion card

As seen in the picture, an expansion card has two main parts, the gold-plated connector that connects to a motherboard expansion slot and the connector plate. The back metal plate often has connections that allow an outside device to communicate with the card and computer. In this example, the modem has two RJ-11 jacks that allow it to communicate over a phone line.

Do laptops or netbooks have expansion cards?

Laptops, netbooks, and other mobile computers do not have expansion cards like what was explained above. However, some laptops can have PC Cards that can be inserted into the side of the laptop. They may also have a Cardbus slot for an ExpressCard to be added.

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