This article is about transformer cores. For the computer memory technology, see Ferrite core ferrite core transformer pdf. In electronics, a ferrite core is a type of magnetic core made of ferrite on which the windings of electric transformers and other wound components such as inductors are formed.
Because of their comparatively low losses at high frequencies, they are extensively used in the cores of RF transformers and inductors in applications such as switched-mode power supplies, and ferrite loopstick antennas for AM radio receivers. Ferrites are ceramic compounds of the transition metals with oxygen, which are ferrimagnetic but nonconductive. They have a low coercivity and are called “soft ferrites” to distinguish them from “hard ferrites”, which have a high coercivity and are used to make ferrite magnets. The exception is with common mode inductors, where the threshold of choice is at 70 MHz.
There are two broad applications for ferrite cores which differ in size and frequency of operation: signal transformers, which are of small size and higher frequencies, and power transformers, which are of large size and lower frequencies. Cores can also be classified by shape, such as toroidal cores, shell cores or cylindrical cores. 1 Watt to 1000 Watts maximum, since more powerful applications are usually out of range of ferritic single core and require grain oriented lamination cores. Typically 10 cm long, these loop antennas are usually hidden inside the radio receiver.