1. (choking coil) An inductor used to present a relatively high impedance to alternating current. Audiofrequency and radiofrequency chokes are used in audio- and radiofrequency circuits, respectively. Smoothing chokes are used to reduce the amount of fluctuation in the outputs of rectifying circuits. Smoothing chokes whose impedance varies with the current passing through them are called swinging chokes.
2. A groove cut to a depth of a quarter wavelength in the metal surface of a waveguide to prevent the escape of microwave energy.