LYCOS RETRIEVER 
Ferrite: Ferrite Cores
built 655 days ago
Ferrite beads are one of the simplest and least expensive types of interference filters to install on preexisting electronic cabling. For a simple ferrite ring, the wire is simply wrapped around the core through the center typically 5 or 7 times. Clamp-on cores are ... available, which can be attached without wrapping the wire at all.
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Ferrite Cores are among the most inexpensive means to reduce EMI in an environment involving preexisting electronic cabling. Some Ferrite Cores require the cable or wire to be wrapped around 6 or 7 times within the core, while other Ferrite Core products simply snap around an existing wire.
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Ferrite toroid cores are used for low power tuned circuits and especially for wideband transformers and baluns for transistor coupling and antenna matching. They have high permeability so you get high inductance with few turns. The low frequency cores are used in switched-mode power supplies. Many Amateur Radio QRP transmitters and receivers will have at least one of these or several.
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Ferrite Cores, sometimes called "Ferrite Beads," are clipped onto cables in order to suppress high frequency noise levels in electronic signals. Ferrite Cores are important for ensuring strong electronic signals through cables in environments where electromagnetic interference can be a problem. The energy Ferrite Cores collect is converted to heat and dissipated.
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Ferrite beads are used to suppress unwanted signals that can interfere with electrical devices such as DC supplies, transmission lines and cables. They provide attenuation of selected frequency bands. The physical shape offerrite beads is similar to a toroidal inductor, but the beads have a greater length to diameter ratio and usually a greater outside to inside diameter ratio than most toroid cores. Different size / shape beads of the same material have different degrees of suppression. The type of ferrite material used to manufacture the bead determines the range of frequencies for suppression purposes, and the physical size and shape of the bead determines the amount of attenuation.In general the impedance is directly proportional to the length of the ferrite beads.
Ferrite cores are used in electronic inductors, transformers, and electromagnets where the high electrical resistance of the ferrite leads to very low eddy current losses. They are commonly seen as a lump in a computer cable, called a ferrite bead, which helps to prevent high frequency electrical noise (radio frequency interference) from exiting or entering the equipment.
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Ferrite Cores