Dampers or “shocks” are devices that can restrict motion through viscous friction, usually paired with an external spring or moving masses such as doors and panels. Dampers generate an opposing force to motion which is directly proportional to velocity.

Dampers are specified by their stroke (distance travelled) and their constant of proportionality (c) between the forces generated the velocity travelled, expressed as Force/ velocity (N/m/s or Lbs/in/s). For example, to control the closing time of a door of mass “M” at the damper pivot point, using a damper stroke “S” at time “T”, a damper with c = M/S/T should be specified.