Why is the inductance when the wire is wound in a circle | GETWELL

The working principle of inductor is very abstract. In order to explain what inductance is, we start from the basic physical phenomena.

Two phenomena and a law-- electromagnetism, magnetoelectricity and Lenz's law

1. Electromagnetism phenomenon

A small magnetic needle is placed next to the electrified conductor, and the direction of the small magnetic needle is deflected, indicating that there is a magnetic field around the current.

If we circle the conductor, the magnetic field generated by each circle of conductor coincides, and the magnetic field as a whole becomes stronger and can attract small objects.

2. (moving) magnetoelectric phenomenon

When a part of the conductor of a closed circuit moves in a cutting magnetic field, electricity is generated on the conductor. The prerequisite is that the circuit and magnetic field are in a relatively changing environment, so it is called "dynamic" magnetoelectricity, and the resulting current is called induced current.

We can do an experiment with a motor. Generally speaking, the ordinary DC has a brush motor, the stator part is a permanent magnet and the rotor part is a coil conductor. Manually rotating the rotor means that the conductor is cutting the magnetic line of force, and the voltage change can be measured by connecting the two electrodes of the motor with an oscilloscope. The generator is made according to this principle.

3. Lenz's law

Lenz's law: the induced current caused by the change of magnetic flux is in the direction of resisting the change of magnetic flux.

The simple understanding of this sentence is that when the magnetic field (external magnetic field) of the conductor's environment becomes stronger, the magnetic field produced by its induced current is opposite to that of the external magnetic field, making the total magnetic field weaker than the external magnetic field as a whole. When the magnetic field (external magnetic field) of the conductor's environment becomes weaker, the magnetic field produced by its induced current is opposite to that of the external magnetic field, making the total magnetic field stronger than the external magnetic field as a whole. According to Lenz's law, the direction of the induced current on the circuit can be determined.

4. What on earth is inductance

Inductance is used to describe the ability of the device to resist the change of current. If the ability to resist the change of current is stronger, then the inductance of the inductor is greater, and vice versa.

For DC excitation, the final inductor is in a short-circuit state (voltage is 0). But in the process of electrification, the voltage and current are not zero, which means that there is power, and the process of accumulating this energy is charging, which stores the energy in the form of a magnetic field and releases energy when needed (such as the current in the steady state cannot be maintained by external excitation).

Inductor is an inertial device in the electromagnetic field, inertial devices do not like change, just like the flywheel in dynamics, it is difficult to rotate at first, but it is difficult to stop once it rotates, and it is accompanied by energy conversion.

This is why winding the wire into a circle is the introduction of inductor. if you want to know more about inductors, please feel free to contact us.