Turntable anti-skating is a feature used in phonograph turntables to prevent skating of the tonearm.
While the angular velocity is constant, the peripheral velocity is not. The angle which the tonearm rests on the record is also different, being small at the beginning of the record but increasing by the end. This increase tends to draw the tonearm toward the center of the record and distort the balance of the sound. To prevent this, a small force is applied at the tonearm when it is near the center. This usually consists of a small counterweight adjustable by a knob.[1]