A damper is a device that provides the resistance of the movement and reduces the energy of the movement. Damping energy absorption is not a new technology. Many kinds of dampers (or shock absorbers) have been used to reduce vibration and energy dissipation in aerospace, aviation, military, guns, automobiles and other industries. Since 1970s, people began to gradually transfer these technologies to construction, bridge, railway and other structural projects, which have developed very rapidly. In particular, a more than 50 year history of hydraulic viscous dampers has undergone a lot of experiments, strict reviews and repeated arguments, especially in the long process of earthquake testing, before being accepted by the structural engineering circles in the United States.

A device that enables the movable part of the instrument to quickly stop at a stable deflection position. In seismic instruments, the damper is used to absorb the inherent vibration energy of the vibration system, and its damping force is generally proportional to the velocity of the motion of the vibration system. There are three main types of liquid dampers, gas dampers and electromagnetic dampers. The damper plays an important role in compensating the small friction and air resistance and improving the frequency response of the vibration pickup system.