How does inductor

Inductors, along with capacitors and resistors, are essential electronic components. So, what is an inductor and how does it work? An inductor is similar to a capacitor in the sense that it stores electrical energy. However, unlike a capacitor, which stores energy in its electrical field, an inductor stores energy in its magnetic field. Where does it get its magnetic field? In the case of an inductor, the amount of energy it can store depends on the strength of its magnetic field. They are a variety of inductor types, but all share one property: the resistance of changes in current.

Conversely, if the current is about to drop, an electromotive force is generated in the direction in which the current is increased. These effects of the induced voltage are produced even when the direction in which the current is flowing is reversed.

Before overcoming the induced voltage that is attempting to block the current, the direction of the current is reversed so that there is no flow of current. The current level remains unchanged when DC direct current flows to the inductor so no induced voltage is produced, and it is possible to consider that a shorted state results.

In other words, the inductor is a component that allows DC, but not AC, to flow through it. When we first start the pump, the water is going to flow and it wants to get back to the pump as this is a closed loop, just like when electrons leave the battery they flow to try and get back to the other side of the battery. Please note- in these animations we use electron flow which is from negative to positive but you might be used to seeing conventional flow which is from positive to negative. As the water flows; it reaches the branches and has to decide which path to take.

As the water keeps pushing, the wheel will begin to turn faster and faster until it reaches its maximum speed. The water will pretty much stop flowing through the reducer and will all flow through the water wheel. As it keeps rotating it will now push the water and act like a pump.

The water will flow around the loop back on its self until the resistance of the pipes and the reducer slows the water down enough that the wheel stops spinning. We can therefore turn the pump on and off and the water wheel will keep the water moving for a short duration during the interruptions. We get a very similar scenario when we connect an inductor in parallel with a resistive load such as a lamp.

When we power the circuit, the electrons are going to first flow through the lamp and power it, very little current will flow through the inductor because its resistance, at first, is too large. The resistance will reduce and allow more current to flow. Eventually the inductor provides nearly no resistance so the electrons will prefer to take this path back to the power source and the lamp will turn off. When we disconnect the power supply, the inductor is going to continue pushing electrons around in a loop and through the lamp until the resistance dissipates the energy.

When we pass electrical current through a wire, the wire will generate a magnetic field around it. We can see this by placing compasses around the wire, when we pass current through the wire the compasses will move and align with the magnetic field.

When we reverse the direction of the current; the magnetic field reverses and so the compasses also reverse direction to align with this. The more current we pass through a wire, the larger the magnetic field becomes.

When we wrap the wire into a coil, each wire again produces a magnetic field but now they will all merge together and form a larger more powerful magnetic field.

We can see the magnetic field of a magnet just by sprinkling some iron filings over a magnet which reveals the magnetic flux lines.

When the electricity supply is off; no magnetic field exists, but when we connect the power supply, current will begin to flow through the coil so a magnetic field will begin to form and increase in size up to its maximum size. The magnetic field is storing energy. When the power is cut, the magnetic field will begin to collapse and so the magnetic field will be converted into electrical energy and this pushes the electrons along. When the current increases they try to stop it with an opposing force.

When current decreases they try to stop it by pushing electrons out to try and keep it the same as it was. So when the circuit goes from off to on, there will be a change in current, it has increased. The inductor is going to try to stop this so it creates an opposing force known as a back EMF or electromotive force which opposes the force which created it. In this case the current is flowing through the inductor from the battery. Some current is still going to flow through, and as it does, it generates a magnetic field which will gradually increase.

As it increases more and more current will flow through the inductor and the back EMF will fade away. The magnetic field will reach its maximum and the current stabilises. The inductor no longer resists the flow of current and acts like a normal piece of wire.

This creates a very easy path for the electrons to flow back to the battery, much easier than flowing through the lamp, so the electrons will flow through the inductor and the lamp will no longer shine.

When we cut the power, the inductor realises there has been a reduction in current. Remember, the magnetic field has stored energy from the electrons flowing through it and will convert this back into electrical energy to try and stabilise the current flow, but the magnetic field will only exist when current passes through the wire and so as the current decreases from the resistance of the circuit, the magnetic field collapses until it no longer provides any power.

If we connected a resistor and an inductor in separate circuits to an oscilloscope, we can visually see the effects.