Inductors in Series

Inductors in series are circuit elements that can store energy in the form of magnetic flux. Unlike capacitors, inductors can be connected in a series configuration without having any mutual coupling between the coils of an inductor.

Just like how different values of resistances connected in a series add together, inductors connected in series also will add their individual inductances. In fact, this is how we obtain the total inductance value for a circuit when using inductors in series.

Definition

Series connections of inductors produce a more complex network whose total inductance is a combination of the individual inductors’ inductances. The formula to calculate the total inductance of a series circuit with inductors is given by integrating the inductances of each individual coil. The inductors must be connected end-to-end such that the flux lines linking them do not affect each other.

An inductor is a two-terminal passive electronic component that stores energy in a magnetic field induced by electric current passing through it. The time-varying magnetic field induces an electromotive force (EMF) or voltage across the conductor. This display link manager EMF opposes the change in current that caused it, according to Lenz’s law of induction. An inductor is most commonly made from an insulated wire wound into a coil to form a magnetic core.

When inductors are connected in a series circuit, the current passes sequentially through each element. This results in each inductor generating its own EMF as the current changes through it, and the total value of this EMF is the sum of all the inductors’ inductances: l = (L1 + L2 + L3 +…) + 1/(Li) + 1/(Ln). Inductors cannot be connected in parallel to one another because their resulting parallel circuits have different paths for the current to take. This is what makes them different from capacitors which can be combined in various ways to achieve the same function of limiting the current and preventing it from flowing backwards through the circuit.

Function

Inductors are passive electrical components that store energy in the form of magnetic flux when a current passes through it. They are also referred to as coils, reactors or chokes and have a core made from ceramic material or iron that is shaped into a toroidal shape to increase their effective radius. The core provides low reluctance path for the magnetic flux that is induced by the current passing through the coil. The inductance of an inductor is defined as the ratio of voltage generated across its terminals to the rate of change of current passing through it. It is measured in Henries (H).

When inductors are connected in series, the overall equivalent inductance increases. This is because the inductance of each individual inductor contributes to the total equivalent inductance. The inductors are also said to be cumulatively or differentially coupled when they have a common direction for the magnetic flux, which helps to add up their overall equivalent inductance.

To understand this inductance property, let’s take 2 inductors of 1mH and connect them in series. Then, use a multimeter to read the inductance by placing the probes on each inductor. You will notice that the reading is doubled when the inductors are connected in series. This is because their self induced emf cancels out. It is the same principle used in capacitors, but inductors are much easier to comprehend than capacitors.

Design Considerations

Inductors in series can be connected in two ways. The first way is called Aiding Method, the current flowing through all coils is the same direction. This way, the magnetic flux of the self inductances of each coil links with each other and add up to the total inductance. The second way is called Opposition Method, in this case the current changes in opposite directions from one coil to another. Then the magnetic flux of each inductor links with its own and with the inductance of the other, the result is a change in the total inductance and the change in the maximum PTE frequency and input impedance.

Choosing the core is also important for inductors used in series. There are many different core types, shapes and sizes available to fit a wide range of applications. In addition to selecting the correct core for an application, designers should consider the effect of the series inductor on MPT and the maximum PTE frequency, as well as the ripple current, voltage and power transfer efficiency.

Inductors are often used in circuits where the current must be changed frequently, this is because they provide fast transient response. However, if the inductance value is too high then there may be Operational Amplifier a large peak current flow that could cause damage. In this case, it is necessary to use a core with gradual magnetic saturation characteristics that can allow the inductance value to recover quickly after the peak current has passed.

Applications

Along with capacitors and resistors, inductors are one of the passive linear circuit elements that make up most electronic components. Inductors temporarily store energy in the form of an electromagnetic field as current passes through them. When the current stops, the magnetic field collapses and the energy is converted back into electric potential energy that’s transferred to other parts of the circuit.

When inductors are connected together in series, they add their magnetic fields to create a single combined field. They also cancel any mutual inductance between them. A voltaic cell can be used to demonstrate this. When 2 inductors are connected in series, the induced voltaic current that’s created across each is equal to the total value of both inductors multiplied by the number of turns in each coil.

Inductors can be combined with other devices that require a magnetic field, including sensors and transformers. The core of a transformer is a stack of laminations made of low-conductivity steel sheets insulated between each other, much like an inductor coil. The result is a compact device that can increase or decrease voltages at high speeds. Transformers are a key component of national electrical grids and can be seen on power poles as the gray canisters.

Inductors are expensive to manufacture due to the copper and iron materials needed. This limits their use and makes them less common than capacitors and resistors. However, they’re an essential component of power supplies and play a crucial role in stabilizing the voltage used.