What are the five devices in which electromagnets can be used? What is the unit of measurement for magnets?

Electromagnets are not only used in industrial devices, but also in some devices related to our daily life, such as speakers and bells. Those who like to study may ask, how are artificial magnets made? Please read on to find out!

Contents of this article

1. Which five devices can electromagnets be used for?

2. What is the unit of measurement for magnets?

3. How are artificial magnets made?

Which five devices can electromagnets be used for?

The applications are as follows:

1. Electromagnetic crane: Install the electromagnet on the crane. After power is turned on, it sucks up a lot of steel. After moving to another position, cut off the current and put the steel down.

2. Electromagnetic relay: Electromagnetic relay is an automatic switch controlled by an electromagnet. Electromagnetic relay can be used to control high voltage and strong current with low voltage and weak current to achieve long-distance operation.

3. Electromagnetic ore concentrator: Electromagnetic ore concentrator is made based on the principle that magnets are attractive to iron ore.

4. Electric bell: When the circuit is closed, the electromagnet attracts the elastic sheet, causing the hammer to move toward the bell. The hammer hits the bell and makes a sound. At the same time, the circuit is disconnected, the electromagnet loses its magnetism, the hammer is bounced back, and the circuit is closed. This process is repeated over and over again, and the electric bell makes a continuous sound.

5. Speaker: A speaker is a device that converts electrical signals into sound signals. It is mainly composed of a fixed permanent magnet, a coil and a conical paper cone. When sound passes through the coil in the speaker in the form of audio current, the magnetic field generated by the magnet on the speaker will exert force on the coil, and the coil will vibrate at different frequencies due to the change in the strength of the current, thereby driving the paper cone to emit sounds of different frequencies and strengths.

What is the unit of measurement for magnets?

Magnetic force or magnetizing force is called magnetic field intensity in physics. Magnetic materials such as steel are good paths for magnetic field lines. The path through which magnetic field lines pass is called a magnetic circuit. In a magnetic circuit, the magnetic potential acting on a unit length is called magnetic field intensity (or magnetizing force). Magnetic field intensity is represented by the letter H.

How are artificial magnets made?

1. Artificial magnets are usually made of steel or some alloys. They are available in bar magnets, needle magnets, horseshoe magnets, round magnets and other shapes according to needs. Artificial magnets, especially rare earth alloys, are not only extremely strong but also much more stable. In the molecules of ferromagnetic materials, due to the movement of electrons, a circular current is formed, called molecular current. Due to the existence of molecular current, each molecule is equivalent to a small magnet.

2. For a ferromagnetic object, when the directions of these small magnets are arranged in a disorderly manner, the magnetism cancels each other out, and the ferromagnetic object does not show magnetism to the outside; when the ferromagnetic object is placed in a magnetic field, due to the effect of the external magnetic field, the directions of these small magnets tend to be consistent, and the ferromagnetic object shows magnetism to the outside. This process is called magnetization. After the external magnetic field is removed, the direction of the arrangement of small magnets in some magnetized ferromagnetic objects can continue to be maintained, and the ferromagnetic object becomes a magnet. Artificial magnets are made based on this principle. When the artificial magnet is heated, the temperature of the magnet rises, the irregular movement of the molecules in the magnet intensifies, and the direction of the arrangement of the small magnets changes to chaos, which causes the magnetism of the magnet to weaken or disappear.