Deflection yoke

A deflection yoke is a kind of magnetic lens, used in cathode ray tubes to scan the electron beam both vertically and horizontally over the whole screen.

By adjusting the strength of the beam current, the brightness of the light produced by the phosphor on the screen can be varied.

The coils are bent into a rough saddle-shape, to conform to the neck of the CRT and to provide a linear magnetic field distribution.

In a color television receiver, three electron beams are all scanned in unison by the single deflection yoke.

In a television receiver, the deflection coil may include ferrite segments to help direct and concentrate the magnetic field.