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A portative electromagnet is one designed to just hold material in place; an example is a lifting magnet. A tractive electromagnet applies a force and moves something. [8] Electromagnets are very widely used in electric and electromechanical devices, including: Motors and generators; Transformers; Relays; Electric bells and buzzers ...
In engineering, a solenoid is a device that converts electrical energy to mechanical energy, using an electromagnet formed from a coil of wire. The device creates a magnetic field [1] from electric current, and uses the magnetic field to create linear motion. [2] [3] [4]
A magnetic lens is a device for the focusing or deflection of moving charged particles, such as electrons or ions, by use of the magnetic Lorentz force. Its strength can often be varied by usage of electromagnets. Magnetic lenses are used in diverse applications, from cathode ray tubes over electron microscopy to particle accelerators.
This category includes devices and components which use near-field magnetism, but excludes radio devices such as antennas. Subcategories This category has the following 7 subcategories, out of 7 total.
Investigation into electromagnetic phenomena began about 5,000 years ago. There is evidence that the ancient Chinese, [1] Mayan, [2] [3] and potentially even Egyptian civilizations knew that the naturally magnetic mineral magnetite had attractive properties, and many incorporated it into their art and architecture. [4]
Electromagnets often use a wire curled up into solenoid around an iron core which strengthens the magnetic field produced because the iron core becomes magnetised. [ 15 ] [ 16 ] Maxwell's extension to the law states that a time-varying electric field can also generate a magnetic field. [ 12 ]
An electric buzzer uses a similar mechanism to an interrupter bell, but without the resonant bell. They are quieter than bells, but adequate for a warning tone over a small distance, such as across a desktop. A buzzer or beeper is an audio signalling device, which may be mechanical, electromechanical, or piezoelectric.
Planar coils are another configuration of coils that are used in MEMS devices to generate force, and are used in sensors and micropumps. Because these coils are flat, they are able to reduce the volume of the device. Speakers are an everyday example of actuation using electromagnetic coils (Figure 2).