Note: Do not rely on this information. It is very old.
Damping, in practical physics, is the diminution in the amplitude of the oscillations of a body by friction of some kind. In many electrical instruments it is necessary that the damping effect on the recording needle shall be vigorous and rapid; the needle quickly takes up its position of equilibrium and is said to be dead-beat. In other instruments we want the friction to be very slight and the decrement in amplitude to be small. In such cases the causes are removed that have a damping effect.