Degaussers and demagnetizers are electrical devices that are used to demagnetize or reduce the magnetic field in components. They produce a very strong magnetic field which is applied to the component. When the component’s magnetic field is exposed to the stronger, fluctuating magnetic field from the degausser or demagnetizer, the magnetic charge of the component is reduced or erased. Degaussing (a form of demagnetizing) is used with audio tapes, video tapes, and computer tapes; computer hard disk drives (HDD) cathode ray tubes (CRT) monitors; and closed circuit television (CCTV). Suppliers of degaussers and demagnetizers may list their products as hard drive degaussers or hard drive erasers, video tape erasers and audio tape erasers, CCTV erasers, and security degaussers.

In terms of technology, there are three basic types of degaussers and demagnetizers: coil, capacitive discharge, and permanent magnet. Coil degaussers have a steel core that is wrapped in copper wire. When activated, they create an alternating electromagnetic field. Because they generate very high levels of heat, however, AC degaussers have a limited duty cycle. Larger coil degaussers and demagnetizers use fans to cool the cool and avoid overheating. Handheld degausser units and conveyor belt degaussing machines are also available. When selecting any type of coil degausser, specifications to consider include power requirements, coil shape, and coil treatment. With conveyor belt degaussers, two degaussing coils are placed at 90-degrees from each other in a V-shaped design. To enhance performance, the degaussing coils are vacuum-dipped and baked.

Capacitive discharge degaussers and demagnetizers generate and store electrical energy in large capacitors. When fully-charged, these capacitors release energy to a coil that creates an intense electromagnetic pulse (EMP). Because this burst of energy is so short, capacitive discharge degaussers don’t overheat and have a continuous duty cycle. Often, these degaussers and demagnetizers are called pulse degaussers. Permanent magnet devices, another type of degaussers and demagnetizers, are also designed for continuous service. Because they produce a high-intensity magnetic field, they are used to erase hard disk drives. Permanent magnet degaussers are available in both manual (handheld) and drawer styles. As their name suggests, they use materials called permanent magnets instead of coil-based electromagnets.