Why do we have lnductors in circuits?

2023-12-08

lnductors are an essential component in electronic circuits, and they serve several important functions.

Here are some key reasons why lnductors are used in circuits:

Energy Storage:

One of the primary functions of an lnductors is to store energy in the form of a magnetic field. When current flows through the coil, a magnetic field is generated around it. This magnetic field stores energy, and when the current changes, the energy is released back into the circuit.

Filtering:

lnductors are often used in conjunction with capacitors to create filters. The combination of lnductors and capacitors can be employed to filter out specific frequencies in a signal. For example, low-pass and high-pass filters utilize lnductors to allow low or high frequencies to pass through while attenuating others.

Inductive Reactance:

In AC circuits, lnductors exhibit a property called inductive reactance. Inductive reactance is the opposition that an lnductors presents to changes in current flow. It is frequency-dependent and is given by the formula X_L = jωL, where ω is the angular frequency and L is the inductance. Inductive reactance is instrumental in the design of AC circuits.

Transformers:

lnductors play a crucial role in transformers. Transformers use the principle of electromagnetic induction to transfer electrical energy between two or more coils. By varying the number of turns in the coils, transformers can step up or step down voltage levels, making them vital in power distribution and electrical systems.

Energy Conversion:

lnductors are used in various energy conversion applications. For example, they are employed in switch-mode power supplies to store and release energy efficiently. lnductors help regulate the flow of current and smooth out voltage fluctuations.

Oscillators and Resonant Circuits:

lnductors are used in oscillators and resonant circuits. In conjunction with capacitors, they can create circuits that resonate at specific frequencies. This property is utilized in radio frequency (RF) circuits, where resonant circuits are employed for tuning and filtering.

Motor Control:

lnductors are integral components in electric motors. The coils in the motor windings create magnetic fields, and the interaction of these fields with each other and external magnetic fields generates the motion in the motor.

Preventing Rapid Changes in Current:

In DC circuits, lnductors resist rapid changes in current. They tend to maintain the current at a relatively constant level, helping to smooth out fluctuations.

In summary, lnductors are versatile components that find applications in a wide range of electronic circuits. Their ability to store energy in a magnetic field, their behavior in AC circuits, and their interaction with other components make them invaluable for tasks such as filtering, energy conversion, and signal processing.

lnductors on a PCB can have various shapes and sizes depending on their specifications and the application. 

Hongda Capacitors provide wide range lnductors to the market. It covers Wire Wound, Molding Type, coil Type, Multilayer Ceramic Type, Multilayer Ferrite Type and Winding Type….

Surface Mount lnductors (SMD):

These are compact lnductors designed for surface mount technology (SMT) on a PCB. They are often small, rectangular components with two metal terminals at either end. The coil may be visible, and a protective casing or coating is applied to the component.

Through-Hole lnductors:

Through-hole lnductors have leads that go through holes in the PCB, and they are soldered to the opposite side. These lnductors may look like small cylinders or have a similar appearance to resistors. They often have color codes or markings to indicate their value.

Toroidal lnductors:

Toroidal lnductors have a doughnut-

shaped (toroid) core. The wire is wound around this core. These lnductors are often used in applications where compact size and high inductance are required. They might be found in power supply circuits.

Custom lnductors Designs:

In some cases, especially in specialized applications, lnductors may have unique shapes or designs tailored to the specific requirements of the circuit. These could include complex coil arrangements or custom casings.
 

When you look at a PCB, the lnductors are typically labeled with a reference designator (e.g., L1, L2) on the silkscreen layer of the PCB, and you can refer to the circuit diagram or bill of materials to identify their specific values and characteristics.

Difference between Capacitors and lnductors

One of the main differences between a capacitor and an inductors is that a capacitor opposes a change in voltage while an lnductors opposes a change in the current. Furthermore, the lnductors stores energy in the form of a magnetic field, and the capacitor stores energy in the form of an electric field. In this article, learn more differences between lnductors and capacitors. 

The listed were a few differences between inductors and capacitors. Both these electrical components impede the flow of electrons in a circuit. Unlike resistors that dissipate energy, capacitors and inductors store energy in an electric field and magnetic field respectively.

 Inductors Used in NFC Circuits

In recent years, the number of smart phone models equipped with NFC features has increased. The following is a brief introduction to NFC technology.

“NFC” stands for “Near Field Communication”, and it enables devices equipped with the feature to communicate over short distances when they are brought within several centimeters of each other. The data transfer speed of NFC is slower than other wireless communication standards such as Bluetooth® and WiFi, so it is used to handle small data volumes. In practical applications, NFC is used for smart phone and wearable device payment services, WiFi settings, and Bluetooth® pairing settings.

As shown below, an NFC circuit is composed of an NFC IC, LC filter, matching circuit, and an antenna.

Figure 1 Composition of an NFC circuit

The LC filter acts as a low pass filter, which removes the high frequency components that are unnecessary for communication from the signal output by the IC. However, because the LC filter is located close to the subsequent matching circuit, the LC filter element constant affects the matching. For this reason, the inductors used in the LC filter must have an inductance with a small deviation. For the same reason, it is also preferable that the inductance of the inductors used in the LC filter be independent of the current value.

In addition, the inductors should be low-loss so that it does not consume more of the battery than is necessary when loss occurs due to the circuit elements. Specifically, it is important that the inductors have a low ACR*1  at a frequency of 13.56 MHz, because this is the frequency of the AC current that flows through the NFC circuit.

*1  ACR(Alternating Current Resistance)

Figure 2 Inductance - AC current (Irms)characteristics 

Figure 3 AC resistance - AC current characteristics

Inductors are required in the circuits that play a role in these kinds of NFC features.  

Hongda Capacitors Inductor Product scope: Wire Wound, Molding Type, coil Type, Multilayer ceramic Type, Multilayer Ferrite Type and Winding Type...

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