Permanent Magnet
a magnet with a force field that will remain all the time
A permanent magnet is a material that produces a magnetic field and retains this magnetism over a long period of time. It is made up of ferromagnetic materials, traditionally iron, nickel, and cobalt, or their alloys. These materials have the unique property of being capable of being magnetized, meaning that their electrons have a spin that creates a magnetic field.
Unlike an electromagnet that requires a flow of electrical current to create a magnetic field, a permanent magnet is a static arrangement of magnetic dipoles that maintains magnetic strength even after the electric field has been removed. They are commonly used in various applications such as speakers, electric motors, MRI machines, and generators.
Permanent magnets can be either naturally occurring or man-made. Natural permanent magnets such as lodestone are rare, and most permanent magnets used today are made of man-made materials that have been magnetized by exposure to a strong magnetic field. Different shapes and sizes of permanent magnets are used depending on their application. For example, bar magnets or horseshoe magnets are commonly used in classrooms to demonstrate magnetic fields, while cylindrical magnets or disk magnets are commonly used in speakers or electric motors.
Permanent magnets have many advantages over other types of magnets in terms of cost, stability, and energy efficiency. They do not require a power source to maintain their magnetic field, making them ideal for portable applications such as magnetic bits for computers, and they have no moving parts to wear out or require maintenance. On the other hand, permanent magnets do have some disadvantages, such as a limited magnetism strength compared to other types of magnets, and the potential for their magnetic fields to interfere with electronic devices.