."..could someone briefly explain what yaw dampers are and how they work? "
It's all done with "strings and mirrors" these days, Speedy...
Modern Yaw Damper systems use computers to calculate what degree of rudder deflection is required to cancel/diminish unwanted aircraft wobbling/oscillation. Inertial Reference Systems and dedicated accelerometers sense the aircraft's pitch, roll, acceleration (and what have you) and send this data to the Yaw Damper Computer(s). The computers then compute the appropriate response and then send commands to actuators in the tail of the aircraft to move the rudder(s) left or right (the movement is limited to a few degrees however and can be overridden by the pilot as required with trim and rudder pedal input).
The response of the Yaw Damper system to destabilizing influences is almost instantaneous. Other than the stable operation of the airplane, the pilot should be oblivious to the corrections supplied by the Yaw Damper system (the rudder pedals do not move when the Yaw Damper is moving the rudder).
On the most modern jetliners, the Autopilot, in most phases of flight, has no influence on the rudder (only elevators and ailerons). In this case, it is up to the Yaw Damper system to provide, damping and turn co-ordination.
Rgds.
Q.