A tuner is a device used to adjust the frequency of a radio or television signal, ensuring that the device receives clear audio or video. Tuners can be found in various forms, including standalone units, built into radios, or as part of television sets. They help users access different channels by selecting the correct frequency. In music, a tuner is an essential tool for musicians to ensure their instruments are in tune. It measures the pitch of a sound and indicates whether it is sharp or flat compared to a standard reference pitch. This helps musicians, such as those playing the guitar or piano, maintain accurate tuning.