Demagnetizer (magnetic eraser), also called demagnetizer.
The degausser usually uses an electromagnet without a closed iron core, and is supplied with an alternating current of 50 Hz. When degaussing, first bring the object to be degaussed close to the degaussing device to make the magnetism reach saturation, and then gradually leave, so the hysteresis loop gradually shrinks until the remanence is eliminated. It can also be used as a demagnetizer by passing the damped oscillating current into the coil of the electromagnet. When using this kind of degausser, the object to be degaussed does not have to leave gradually.