The sound card> is an expansion card that contains electronics for audio input and output. The card plays digital audio>, which is sound that has been translated into a bunch of numbers and stored on disk. Audio CDs are an example of digital audio.

Sound cards can also synthesize sound or generate its own tones just like an electronic keyboard. In other words, the card can make musical tones "on the fly."

Finally, this card can record digital audio and store it as a WAV file> on your PC's hard drive>, such as recording sound through a microphone connected to the sound card. However, be cautioned, digital sound takes up a lot of disk space.

Most sound cards are Sound Blaster> and AdLib> compatible. These are the two industry standards for sound. Creative Lab's Sound Blaster standard leads the way in digital sound, while Adlib's standard leads the way in synthesized sound.

For sound creation and reproduction, sound cards come in different flavors including 8-bit>, 16-bit>, 32-bit>, 64-bit>. The higher the bit number, the more accurate the sound will be.