The role of SMD inductor and principle
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General electronic circuit inductance is hollow coil or coil with a core, only through a smaller current, withstand lower voltage; and power inductors also hollow coil, but also with a magnetic core, the main feature is the use of Coarse wire wound, can withstand dozens of security, hundreds, thousands, even tens of thousands of security. Power chip inductors are split with and without the magnetic shield two, mainly composed of core and copper. In the circuit mainly from the role of filtering and oscillation.
Introduction to the principle of chip inductors:
Inductance is a property of a closed loop, that is, when the current through the closed loop changes, the emf appears to counteract the change in current. This inductance is called self-inductance and is the property of the closed loop itself. Assuming that the current in a closed loop changes, the electromotive force is induced in another closed loop due to the induction. This type of inductance is called mutual inductance. When two inductive coils are close to each other, the change of the magnetic field of one inductive coil will affect the other inductive coil. This effect is mutual inductance. The size of the mutual inductance depends on the degree of coupling of the inductance of the inductance coil and the two inductance coils. Components made using this principle are called mutual inductor.
Chip inductor effect:
The role of SMD inductors is insulated wire wrapped around the electromagnetic induction components. Belongs to the commonly used inductance components. The role of chip inductors: through the DC resistance AC This is a simple statement, the AC signal isolation, filtering or capacitors, resistors and other components of the resonant circuit. The role of tuning and frequency-selective inductors: inductors and capacitors in parallel with the LC can be composed of tuning circuit. Chip inductor any current in the circuit, will produce a magnetic field, the magnetic flux of the magnetic field and acting on the circuit.
When the current through the SMD inductor changes, the DC voltage potential generated in the chip inductor will prevent the current from changing. When the current through the inductor increases, the self-induced electromotive force generated by the inductor coil and the current through the inductor decreases, the self-induced electromotive force is in the same direction as the current, preventing the current from decreasing and releasing the stored energy to Reduce the compensation current. In the opposite direction of the flow, the increase of the current is prevented, and at the same time, a part of the electric energy is converted into a magnetic field and stored in the inductor; therefore, not only the ripple of the load current and the voltage decreases but the waveform becomes smoother after the inductor filter, Angle increases.
Shielding chip inductors and the role of the general chip inductor is not the same, the general chip inductor in the circuit is not shielded, the use of the inductance in the circuit can not achieve the desired effect, the shield chip inductor can be shielded Some circuits in the current instability, a good barrier to play, the shield of a complete metal shield will be surrounded by a positive conductor, the shield inside will be induced with the same amount of negative charge on the conductor, If the metal shield is grounded, the positive positive charges on the outside will flow into the ground. There will be no electric field on the outside. That is, the electric field with the positive conductor is shielded in the metal shield.
Shielding inductance in the circuit also played a role in the coupling, the shield chip inductor to reduce the alternating electric field of the coupling circuit to the interference voltage, the inductor can interfere with the source and the sensitivity of the circuit set up a good metal shield, and Metal shield grounding. The magnitude of the coupling interference voltage of the alternating electric field to the sensitive circuit depends on the product of the alternating electric field voltage, the coupling capacitance and the grounding resistance of the metal shield. As long as the metal shielding body is properly grounded, the coupling interference voltage of the alternating electric field to the sensitive circuit can be made small. Electric field shielding to reflect the main, so the shield body thickness does not have to be too large, but the structural strength as the main consideration.