Magnetic effect from electric current

Get to know the magnetic effect of electricity

• If you deal with the magnetic effects of electric current in physics class, you will learned that the discovery by the Danish physicist Hans Christian Oersted was made around 1820. You also call this phenomenon electromagnetism.
• Note that the direction of the magnetic field depends on the direction of the current. If the direction of the current is reversed, the magnetic field lines, which form concentric circles in a straight conductor, immediately run in the opposite direction.
• You can find out the course of the field lines by holding the current-carrying conductor with your right hand and spreading your thumb upwards in the direction of the current. The fingers form the direction of the magnetic field lines.
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• If two conductors run parallel to each other and the current flows in the same direction in both, you will notice that a ring-shaped magnetic field is created around both conductors. Remember that the stronger the current in the conductors, the greater the force of attraction.
• It is interesting to know that winding a wire into a coil causes the inside of the coil to become The effects of the magnetic fields from each section of conductor add up, so that the current-carrying coil acts like a bar magnet behaves. They call the magnetic fields that leave the coil the North Pole, and those that have entered the South Pole of the electromagnet.


What is an electromagnet?

An electromagnet is actually an iron core covered with wire, which is attached to a ...

• You can multiply the magnetic effect of the electromagnet if there is a soft iron core in the coil. In the iron core, all magnetic elementary areas are aligned in the direction of the electromagnetic field.
• Note that when you turn off electrical power, the magnetism disappears except for a small remainder. The magnetism left in iron is called remanent magnetism.
• Bring hard magnetic material such as steel into one of direct current for long periods of time If the coil flows through it, the magnetic elementary areas remain uniform even after the power is switched off aligned. This is how you make permanent magnets.

Apply electromagnetism from electric current

• It is interesting that electromagnetism has found many uses. So you should know that one of the first was the Morse code machine, the heart of which is an electromagnet. By pressing the Morse button, the current flows through the coil and the Morse code is put on paper.
• The door knocker was also replaced by the electric doorbell. You call the device Wagner's hammer and it is based on the fact that when the bell button is pressed, the circuit is closed and the electromagnet attracts the clapper. Due to the attraction, the flowing current is interrupted and the electromagnetism is extinguished so that the clapper can spring back.
• Current-carrying coils with soft iron cores are also used as strong lifting magnets. You can observe that the holding force of the magnets can carry many tons of steel and that the steel parts are only deposited by switching off the current.
• The magnetic effect of the electric current can also be used in a relay. In this case, an electromagnet pulls an armature rocker against a spring when the coil is flowing through it, a switch A, which you also call the normally closed contact, is opened and another switch B, called the normally open contact, is closed.
• An alarm system is an example for you of the use of the normally open contact. The relay is constantly energized, which attracts the armature against the spring. In addition, a bell is connected to a battery via switch W, the root of the relay, and to the switch connection for the normally open contact. If a burglar interrupts the power supply to the relay, for example by unscrewing the house fuse, the bell rings the alarm.