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In our day-to-day life, we encounter different magnets like bar magnets, horseshoe magnets, sphere magnets, disc magnets, cylindrical magnets, and many more. We all know that these magnets have two poles: the north and south poles. These magnets are called permanent magnets. Their magnetic force stays for a long time until the materials from which they are made are not affected by external factors. At the same time, another type of magnet is a temporary magnet that has a temporary magnetic effect. Let’s see in brief about both magnets.
Electromagnet (Temporary magnet)
Electromagnets are also called temporary magnets. They work on the principle of electromagnetism (induction of magnetic effect due to the flowing electric current)
Temporary magnets are made of a soft iron core. This core is wrapped by a long coil of insulated copper wire. When the current is passed from the coil, the core gets magnetised. Thus, the magnetic effect of the electromagnet is only for a time when the current is passing through the coil.
The various factors that determine the magnetic field of an electromagnet are – turns in the coil, current flowing through the coil, and the distance between the two poles. It is used in transformers.
Permanent Magnet
Permanent magnets can retain their magnetism and magnetic properties for a longer time. Hard materials with strong magnetic properties are used to make a permanent magnet. A bar is the best example of a permanent magnet. They are appropriate magnets to explain the behaviour of the magnet, i.e. magnetic field line, the attraction of poles, and many more.
Benefits of Electromagnets over Permanent Magnets
- Electromagnets are cheaper compared to permanent magnets. The reason behind this is the lower cost of production of electromagnets due to the cheap materials used to make them. Permanent magnets need costlier materials.
- The strength of electromagnets can be changed as per our needs by altering the factors affecting their magnetic strength. But this is not possible in a permanent magnet.
Drawbacks of Electromagnets
- They require a large number of copper couplings, due to which they can’t be used in small spaces.
- They are sensitive, need a lot of maintenance, and have the chance of getting damaged due to short circuits.
- They require a continuous electric current supply. Therefore there is the chance that once in a lifetime, the magnet and its field will get affected by any of the factors like ohmic heating, Inductive voltage spikes, core losses, the coupling of coils, etc.
Drawbacks of Permanent Magnets
- The magnetic field of a permanent magnet can be produced until a specific temperature. This feature of these magnets makes them unfit for hot device applications.
- Permanent magnets are made of materials that have magnetic characteristics. This material corrodes with time leading to corrosion of the magnet. Corrosion reduces the strength of the magnetic field.
- The poles of a permanent magnet cannot be changed.
Difference Between temporary magnet (Electromagnet) and Permanent Magnet | |
Electromagnet | Permanent Magnet |
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2.Current flow decides the strength of the magnetic strength. | 2.The material used for the making of a magnet decides the magnetic strength. |
3.Magnetic properties can be removed temporarily. | 3.No temporary removal of magnetic properties takes place. Once removed can never be retained. |
4.A magnetic field can be maintained only if the current supply is continuous. | 4.No need for the current supply to maintain the magnetic field. Naturally possess the magnetic property. |
5.Made of soft materials. | 5.Made of hard materials. |
6.Poles can be altered by changing the direction of the current flow. | 6.Poles cannot be altered. They are fixed at the position. |
7.Used in electric fans, electric bells, telegraph, debit cards, credit cards, etc. | 7.Used in microphones, speakers, electrical devices like generators, motors, scientific instruments, etc. |
Conclusion
Thus we can conclude that electromagnets are temporary magnets that work on the principle of electromagnetism (induction of magnetic effect due to the flowing electric current). Permanent magnets can retain their magnetism and magnetic properties for a longer time. The cost of producing an electromagnet is low compared to that of a permanent magnet. The magnetic field of an electromagnet is dependent on the factors like turns in the coil, a current flowing through the coil, and the distance between the two poles. In contrast, permanent magnets’ magnetic field is dependent on the material it is made of.
