The Online Encyclopedia and Dictionary







A pedal is a lever activated by one's foot. Examples include:

  • An automobile has usually three pedals, from left to right:
    • operated by the left foot:
    • operated by the right foot:
      • brake pedal, which is usually wide and elevated well above the car floor
      • gas pedal (accelerator): controls fuel supply to the automobile's engine. It is usually narrow and close to the car floor allowing the driver's heel to rest on the car floor.
  • Bicycle pedal: on a bicycle, each of two platforms at the end of the crankarms, connected such that while the crank arms rotate, the pedals can stay parallel to the shoe soles; this human powered rotation provides the propulsion, usually through a bicycle chain that makes the back wheel turn. In the case of a back pedalling brake, they are also used for applying the brake in the back wheel, again through the chain.
  • Most pianos have two or three piano pedals (from left to right):
    • A soft pedal which causes the hammer to hit only two strings of a note instead of three. This creates a "softer" sound.
    • A sostenuto pedal (usually the one missing if the piano has only two pedals) works similar to the damper pedal except only the notes being played when the pedal is depressed are sustained.
    • A damper pedal (sometimes called the sustain pedal) which causes notes to sustain after the key for that note has been released.
  • Pipe and electronic organs have a variety of pedals, some of which are:
    • The pedalboard, which contains approximately one dozen to three dozen pedals that resemble the keyboards (or "manuals"); when one of these pedals is depressed, it causes a note (or group of notes) to sound.
    • One or more expression pedals, which effectively control the volume either of the music overall or of discrete divisions; as the organist increases pressure, the power of her music increases.
    • A crescendo pedal, with which the organist progressively adds stops as she presses down more and more firmly.
    • An effects pedal, which, on electronic organs, may be programmed to alter pitch or perform other functions.

Geometry: see also pedal triangle, pedal curve.

The contents of this article are licensed from under the GNU Free Documentation License. How to see transparent copy