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Difference between Permanent Magnet and Electromagnet
A magnet is a material or object which has ability to produce a magnetic field and can attract or repel other ferromagnetic materials. Based on the method of production of magnetic field, the magnets are classified into two types viz. −
Permanent magnet
Electromagnet
The main difference between an electromagnet and a permanent magnet is that an electromagnet produces the magnetic field by the effect of electric current flowing through a coil insulated wire wound around a piece of soft magnetic material. Whereas, a permanent magnet is made up of hard magnetic material and once it is magnetized, it can produce the magnetic field over a long period of time. Other differences between permanent magnet and electromagnet are shows in the table below.
What is a Permanent Magnet?
A permanent magnet is the type of magnet whose magnetism is permanent. In other words, an object made from a material that is magnetized and able to create its own magnetic field for long periods of time is known as a permanent magnet.
A permanent magnet retains its magnetism even after the removal of the magnetizing force. The permanent magnets are made from hard ferromagnetic materials like ferrite, alnico, etc. A common method of making permanent magnets is the heating of a ferromagnetic material to a very high temperature. The permanent magnets are used in several applications such as electric motors, refrigerator doors, speakers, memory devices, etc.
What is an Electromagnet?
A type of magnet which consists of a coil of insulated wire wound around a soft ferromagnetic material and produces the magnetic field by flow of electric current through the coil is known as an electromagnet.
The strength of the magnetic field produced by an electromagnet depends upon the value of electric current flowing through the coil. The magnetism of an electromagnet disappears when the electric current in the coil is turned off. The electromagnets are widely used in electrical machines, measuring instruments, cranes and hoists, etc.
Difference between Permanent Magnet and Electromagnet
The major differences between electromagnets and permanent magnets are highlighted in the following table −
| Basis of Difference | Permanent Magnet | Electromagnet |
|---|---|---|
| Definition | An object made up of a magnetic material and is able to produce a magnetic field permanently, i.e. even after the removal of source of magnetization is known as a permanent magnet. | A type of magnet which uses electric current to produce the magnetic field is known as electromagnet. |
| Nature of magnetic field | As the name implies, a permanent magnet shows its magnetic behavior forever, i.e. permanent magnetic field. | Electromagnets are temporary in nature, their magnetic field disappears when electric current is turned off, i.e. temporary magnetic field. |
| Magnetic material used | The hard ferromagnetic materials such as steel are used to form the permanent magnets. | The electromagnets are made of soft ferromagnetic materials such as soft iron. |
| Need of electric current | Permanent magnets do not need an electric current to show the magnetism. | Electromagnets require an electric current to behave as a magnet. |
| Production of magnetic field | Permanent magnets produce the magnetic field by its self. | Electromagnets produce the magnetic field by using the magnetic effect of electric current. |
| Change in magnetic field | The strength of the magnetic field of a permanent magnet cannot be changed. | The magnetic field strength of an electromagnet can be easily altered by changing the current in the coil. |
| Strength of magnetic field | The permanent magnets produce relatively weaker magnetic field. | The magnetic field produced by an electromagnet can be very strong as compared to that of the permanent magnet. |
| Change of polarity | The polarity of permanent magnets cannot be changed or reversed | The polarity of electromagnets can be reversed by reversing the direction of electric current in the coil. |
| Demagnetization | The magnetism of permanent magnets cannot be made zero, i.e. they cannot be demagnetized. | By switching off the current through the coil, the electromagnets can be easily demagnetized. |
| Coercivity | Permanent magnets have high Coercivity. | The Coercivity of electromagnets is low. |
| Common examples | The most common example of permanent magnet is ‘bar magnet’. | One common example of electromagnet is ‘solenoid’. |
| Applications | The permanent magnets are widely used in computers, small electric motors, cars, headphones, speakers, refrigerator door magnet, etc. | The electromagnets are extensively used in large electric motors, generators, fans, transformers, electric buzzers and bells, induction cooker, MRI machines, magnetic locks, etc. |
Conclusion
In this article, we discussed several key differences between permanent magnets and electromagnets. Each of these magnets has its own advantages and are extensively used in various fields as required.
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