Abstract: A degaussing system for color monitors is disclosed. During a degaussing cycle, the system successively reverses the coupling in a bridge circuit between a degaussing coil and a storage capacitor so as to generate oppositely directed degaussing currents through the coil. To insure that the residual magnetism after degaussing is substantially zero, feedback signals are developed in a feedback circuit and applied through a control circuit to the bridge circuit to successively decrease the coil's current magnitudes until they reach a predetermined threshold. Simultaneously, the feedback signals are adjusted to cause the time-integrated current in one direction of the coil to substantially equal the time-integrated current in the other coil direction.

Abstract: A magnetic compensation system for a CRT display that includes a magnetic shield and a compensation coil for generating a bucking field is disclosed. The magnetic shield houses the CRT and shunts the transverse component of an external magnetic field. An annular metal face plate is attached to the shield at its open end and extends inward from the edges of the shield in a plane substantially parallel to the display. The compensation coil is disposed on the face plate's outer surface, and provides a bucking magnetic field to oppose the axial component of the external magnetic field in response to a drive signal. A pair of magnetic field sensors for sensing the difference between the external and bucking fields are spaced inward from the coil and opposite each other. The sensors are positioned substantially perpendicular to the plane of the face plate at its inner edge.