An electronic circuit that locks on to a selected carrier frequency (station, channel). Found in every AM/FM radio, TV, cellphone and wireless receiver, the tuner filters out all but the desired frequency and passes it on to other stages in the device to extract the audio, video or data. See TV tuner
Try Tuning This Radio!
In 1925, users had to tune three stages on this battery-operated Stewart Warner Radio to obtain a radio station. When they got a good signal, they wrote down the numbers on a log sheet (top) so they could tune in quickly the next time. (Equipment courtesy of Vintage Radio and Communications Museum of Connecticut, www.vrcmct.org)