smd inductor working principle

author: MagTop
Inductance is the ratio of the magnetic flux of the wire to the current that produces this magnetic flux when an alternating current is passed through the wire, which generates an alternating magnetic flux around the interior of the wire. When a DC current is passed through the inductor, there are only fixed magnetic lines of force around it, which do not change with time; however, when an AC current is passed through the coil, there will be magnetic lines of force around it that change with time.

According to Faraday's Law of Electromagnetic Induction--Magnetic Electricity Analysis, the changing magnetic field lines will generate an induced potential at both ends of the coil, which is equivalent to a "new power supply". When a closed loop is formed, this induced potential will generate an induced current. It is known from Lenz's law that the total amount of magnetic lines of force generated by the induced current should try to prevent the changes of the magnetic lines of force. The change of the magnetic line of force comes from the change of the external alternating power supply, so from the objective effect, the inductance coil has the characteristic of preventing the current change in the alternating current circuit. The inductance coil has characteristics similar to the inertia in mechanics, and is named "self-induction" in electricity. Usually, sparks will occur at the moment when the knife switch is opened or the knife switch is turned on. caused by high induced potential.

Inductors have the property of blocking the passage of alternating current and allowing direct current to pass smoothly. The higher the frequency, the greater the coil impedance. Therefore, the main function of the inductor is to isolate and filter the AC signal or form a resonant circuit with capacitors, resistors, etc.