A magnetic core is a component made from ferromagnetic materials, such as iron, that enhances the magnetic field in electrical devices. It is commonly used in transformers, inductors, and magnetic coils to improve efficiency by concentrating magnetic flux and reducing energy losses. These cores can be found in various shapes, including toroidal and laminated forms, to optimize performance. The design of a magnetic core is crucial for applications in electrical engineering and electronics, as it directly affects the device's ability to store and transfer energy effectively.