How To Identify SMD Inductor? And How To Know Its Value?

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Inductors are used in many electrical and electronic applications; they store electrical energy in the form of magnetic energy. The inductors can be used only with the alternating current because they have frequency, which changes the magnetic flux. Inductors can be mounted on the surface of computer boards, and they are known as SMD inductors. So, how to identify SMD inductor?

How To Identify SMD Inductor?

To identify an SMD inductor, you need to use a multimeter; it can be either a digital multimeter or an analog one. Inductors don’t have resistance, so you have to measure the resistance of the component; you can follow these easy steps:

1. Adjust your multimeter to Ohm, so you can measure the resistance. 
2. Set the multimeter to the highest resistance available.
3. Observe the reading; it’s a surface mount inductor if it shows zero ohms.
4. If the reading has a constant value, it’s a resistor, except if the value was 1.
5. If the reading starts small and then increases gradually to it reaches one and then settles on it, it’s a capacitor. If you removed the probes for 2-5 seconds and then measured again, the reading will do the same; therefore, you can be certain it’s a capacitor.

How To Identify Inductors Value?

To identify the value of an inductor, you have to look for the numbers found on its body or packaging; you will find three digits; the first two represent the absolute value of the inductance; meanwhile, the last number represents the power of ten, for example, if it’s 450 it means 45H.

The H symbol is the unit of the inductance, where 1000mH equals 1H, and 1000μH equals one mH.

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What is an SMD Inductor?

SMD inductors are also known as surface mount inductors; they are placed through surface mount manufacturing. Surface mount inductors are passive parts in the boards; they are factors optimizing in many circuits and applications as they are positive reactance components.

When installed in circuits, they are used mainly in power supplies, filtering, and many other functions. Therefore, inductance is linked with a PCB trace found in any passive component or circuits integrated with wire bonds. 

What Are The Sizes of SMD Inductors?

Surface mount inductors have many styles and sizes, such as thin film and multilayer thick film depositions, and wire-wound styles. In addition, there are other inductor types, for example:

• Toroidal and Wire-wound
• Air and Ferrite Cores

The core inductor can be made of many different materials, for example:

• Carbonyl Powder
• Air
• Ferrite
• Iron
• Metal Composite
• Non-magnetic
• Phenolic
• Polymer
• Powdered Iron

Are SMD Inductors Polarized?

No, SMD inductors are not polarized; in general, any inductor isn’t polarized. Such as resistors, inductors can be placed due to their construction and physics design. Although they are not polarized, the current passing through them can change or affect the magnetic poles around inductors.

Inductors and resistors have many similarities; however, the inductors differ in that they are used to keep electrical energy in magnetic energy. Therefore, inductors are made of different materials other than what materials are used to construct resistors.

Can SMD Inductors Use DC Current?

No, surface mount inductors can’t use direct current like any other inductors. Instead, the inductor’s main job is to store electrical energy as magnetic energy, so it depends on the current changing its direction and producing magnetic flux such as alternating current.

The direct current only has one direction and doesn’t change its direction during time intervals like an alternating current. Therefore, the direct current has zero frequency, meaning no change in the magnetic flux.

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What Are Inductor Types?

Inductors have many different uses and shapes; the inductor’s size depends on the martial used to construct it. Inductors are divided into two main groups variable and fixed; if an inductor has a silver color, it’s a fixed inductor according to the color coding. Meanwhile, a dumbbell-shaped inductor has a few Henries.

The core material is an essential factor in the inductor; the core is considered the heart of the inductor. There are many types of inductors with different core materials, for example: 

The Air-core Inductor

The air is the core material in the air-core type; it’s the most common type, with only a winding air-core as its core. In addition to air, non-magnetic materials can also be used in air-conductors such as ceramic and plastic. However, this type is used mainly in applications with high magnetic field strengths.

The air-core offers minimum loss of signals because no metal material is used in the core; instead, the air is used as the core.

The Iron-Core Inductor

The core of the iron-core inductor is made of ferromagnetic materials such as iron or ferrite. These materials are used in cores to increase the inductance of the inductor because they have high magnetic permeability. Magnetic permeability is the ability of a material to form magnetic fields in the materials. 

Although ferromagnetic materials increase the inductor’s inductance, they are subject to energy and core losses when they face a high frequency. Usually, this type of inductor is used in types of transformers.

The Toroidal Inductors

The toroidal inductors have a circular shape, and their core is made of magnetic materials with a wire wound around it. This type suffers a minimum loss in its core due to the symmetry achieved by its circular design. The main current type used with the toroidal inductors is the alternating current.

The Laminated Core Inductors

The laminated core inductor has laminated sheets as its core; laminated sheets can be stacked. When the current travel more inside an inductor, the more energy it loses, so the loss is bigger if the loop gets longer. The eddy currents are prevented in the laminated inductors due to the laminated sheets used as the inductor’s core.

The construction of the laminated core inductors gives them a big advantage over other inductors as they suffer a minimum loss of energy; they are mainly used in transformers manufacturing.

The Powdered Iron Core Inductors

The powdered iron core inductor differs from an iron core because it’s not only made of magnetic materials it also has air gaps inside its core. The major advantage that powdered iron core inductors have is that they can store high energy levels. In addition, they suffer very minimum hysteresis and eddy current losses. 

You can find powdered iron core inductors at very low prices, and they have excellent stability when it comes to their inductance.

Conclusion

To sum up, you need to use a digital or analog multimeter to identify a surface mount inductor. Inductors don’t have resistance, so you have to measure the resistance of the component; you can follow these easy steps:

1. Adjust your multimeter to Ohm, so you can measure the resistance. 
2. Set the multimeter to the highest resistance available.
3. Observe the reading; it’s a surface mount inductor if it shows zero ohms.
4. If the reading has a constant value, it’s a resistor, except if the value was 1.
5. If the reading starts small and then increases gradually to it reaches one and then settles on it, it’s a capacitor. If you removed the probes for 2-5 seconds and then measured again, the reading will do the same; therefore, you can be certain it’s a capacitor.

You can know the value of any SMD inductor by looking for the numbers found on its body or packaging; you will find three digits; the first two represent the absolute value of the inductance; meanwhile, the last number represents the power of ten, for example, if it’s 450 it means 45H.