Chopping

(electronics) The removal, by electronic means, of one or both extremities of a wave at a predetermined level.
(physics) The act of interrupting an electric current, beam of light, beam of infrared radiation, or stream of neutrons at regular intervals.

The act of interrupting an electric current, beam of light, or beam of infrared radiation at regular intervals. This can be accomplished mechanically by rotating a vibrating mirror in the path of the beam to deflect it away from its intended source at regular intervals. A current can be chopped with an electromagnetic vibrator having contacts on its moving armature. A current can also be chopped electronically by passing it through a multivibrator or other switching circuit. Chopping is generally used to change a direct-current signal into an alternating-current signal that can more readily be amplified. See also Multivibrator.

Chopping has been increasingly used inside analog integrated circuits. Solid-state switches and capacitors are used to chop operational amplifiers, greatly improving their offset voltages. Chopping is also used in analog large-scale-integrated switched-capacitor filters as a means for reducing their undesirable 1/f (inverse-frequency) noise. See also Amplifier; Integrated circuits; Operational amplifier; Switched capacitor.