What is the primary function of an adapter card in a computer?

The primary function of an adapter card in a computer is to communicate with devices both inside and outside the case. Adapter cards, which include components like graphics cards, sound cards, and network interface cards, provide essential interfaces for the computer to connect and interact with various hardware components and peripherals. For example, a graphics card allows the computer to output images to a monitor, while a network interface card facilitates connection to networks or the internet. By performing this role, adapter cards enhance the computer's capabilities by enabling it to work with additional devices and improve overall functionality.

In contrast, increasing the computer's processing speed typically involves upgrades to the CPU or RAM rather than simply utilizing adapter cards. Storing firmware data is a function more associated with specific components like the motherboard's BIOS or flash storage, not adapter cards. Managing power supply to the motherboard is a task performed by the power supply unit and voltage regulators, rather than by adapter cards designed for communication and expansion.