Imagine water flowing through a system of pipes. There’s a pump that pushes the water, similar to how a battery powers an electrical circuit. The pipes split into two branches. One branch has a narrower section, making it harder for water to pass through—this is like resistance in a circuit. The other branch has a water wheel that turns as water flows through it. This wheel is heavy, so it takes time to start moving. This water wheel represents an inductor in an electrical circuit.
When the pump starts, water flows through the pipes, trying to return to the pump, just like electrons flow from one side of a battery to the other. In our example, we use electron flow, which moves from negative to positive, but you might also learn about conventional flow, which goes from positive to negative. Both are important to understand.
As water reaches the branches, it chooses the easier path. Initially, the water wheel is hard to turn, so water prefers the path with the narrower section. Over time, as water keeps pushing, the wheel spins faster, reducing resistance. Eventually, water flows more easily through the wheel than the narrow section.
When the pump is turned off, the water wheel keeps spinning due to inertia, acting like a pump itself. It continues to push water around the loop until resistance slows it down. This is similar to how an inductor works in a circuit.
In a circuit with an inductor and a resistive load like a lamp, when powered on, electrons first flow through the lamp. The inductor initially resists the flow, but as it builds a magnetic field, it allows more current to pass. Eventually, the inductor offers little resistance, and electrons prefer this path, causing the lamp to turn off.
When the power is disconnected, the inductor continues to push electrons around the circuit, keeping the lamp lit until the energy dissipates. The magnetic field created by the inductor stores energy. When the power is cut, the field collapses, converting back into electrical energy to maintain current flow.
Inductors resist changes in current. When current increases, they create an opposing force called back electromotive force (EMF). This back EMF opposes the current that created it. As the current stabilizes, the inductor stops resisting and acts like a regular wire, allowing easy electron flow.
When the power is cut, the inductor tries to maintain the current by releasing stored energy, lighting the lamp briefly. The magnetic field only exists while current flows, and as resistance slows the current, the field collapses, stopping the power.
That’s how inductors work! They play a crucial role in managing current flow in circuits. To learn more, explore additional resources and videos on this topic. Keep experimenting and discovering the fascinating world of electronics!
Using household materials, build a simple water flow model to represent an electrical circuit with an inductor. Use a small pump, tubing, and a water wheel to visualize how water flow changes over time. Observe how the water wheel behaves when the pump is turned on and off, and relate this to the behavior of an inductor in a circuit.
Explore an online circuit simulation tool to build a virtual circuit with an inductor and a resistive load. Experiment with turning the power on and off, and observe how the inductor affects the current flow. Take note of how the lamp behaves in response to changes in the circuit.
In small groups, discuss the analogy between water flow and electrical circuits. Prepare a short presentation explaining how inductors work, using the water wheel analogy. Present your findings to the class, highlighting key concepts like resistance, back EMF, and energy storage.
Conduct a hands-on experiment using a simple circuit kit that includes an inductor. Measure the current flow with and without the inductor in the circuit. Record your observations and explain how the inductor influences the circuit’s behavior over time.
Research real-world applications of inductors in electronic devices. Write a short report on how inductors are used in technologies such as transformers, radios, or power supplies. Share your report with the class to deepen everyone’s understanding of the practical uses of inductors.
Sure! Here’s a sanitized version of the transcript:
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I want you to first think about water flowing through some pipes. There is a pump that pushes this water, and the pump is equivalent to our battery in the circuit. The pipe will split into two branches, and the pipes are equivalent to our wires. One branch has a pipe with a reducer in it, and that reduction makes it a little harder for water to flow through it. So, the reducer is equivalent to resistance in our electrical circuit. The other branch has a water wheel built into it. The water wheel can rotate, and the water flowing through it will cause it to rotate. The wheel is very heavy, though, so it takes some time to get it up to speed, and the water has to keep pushing against this to get it to move. This water wheel is going to be equivalent to our inductor.
When we first start the pump, the water is going to flow and wants to get back to the pump, as this is a closed loop. This is just like when electrons leave the battery; they flow and try to get back to the other side of the battery. In these animations, I use electron flow, which is from negative to positive, but you might be used to seeing conventional flow, which is from positive to negative. Just be aware of the two and which one we’re using.
As the water flows, it reaches the branches and has to decide which path to take. The water pushes against the wheel, but the wheel is going to take some time to get moving, adding a lot of resistance to the pipe, making it difficult for the water to flow through this path. Therefore, the water will instead take the path of the reducer because it can flow straight through this and get back to the pump much easier. As the water keeps pushing, the wheel will begin to turn faster and faster until it reaches its maximum speed. Now, the wheel doesn’t provide almost any resistance, so the water can flow through this path much easier than the path with the reducer in it. The water will pretty much stop flowing through the reducer and will all now flow through the water wheel.
When we turn off the pump, no more water will enter the system, but the water wheel is going so fast it can’t just stop; it has inertia. As it keeps rotating, it will now push the water and act like a pump. The water will flow around the loop back on itself until the resistance in the pipes and the reducer slows the water down enough for the wheel to stop spinning. We can therefore turn the pump on and off, and the water wheel will keep the water moving for a short duration during these interruptions.
We get a very similar scenario when we connect an inductor in parallel with a resistive load, such as a lamp. This is the same circuit as we just saw, but I’ve wired it more neatly. 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 rather than through the lamp, causing the lamp to 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 the electricity supply is off, no magnetic field exists, but when we connect the power supply, current will begin to flow through the coil, and a magnetic field will begin to form and increase in size up to its maximum. The magnetic field is storing energy. When the power is cut, the magnetic field will begin to collapse, and this will convert the magnetic field into electrical energy, pushing the electrons along.
In reality, this happens incredibly fast; I’ve just slowed these animations down to make it easier to see and understand. So why does it do this? Well, inductors don’t like changing current; they want everything to remain the same. When the current increases, they try to stop it with an opposing force. When the current decreases, they try to stop it by pushing electrons out to try and keep it stable. 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 and create an opposing force, resulting in back EMF or electromotive force. This back EMF opposes the force that created it—in this case, that’s the current flowing through the inductor from the battery.
Some current is still going to flow through, though, and as it does, it generates a magnetic field that will gradually increase. As it increases, more and more current will flow through the inductor, and the back EMF will eventually fade away. The magnetic field will reach its maximum, and the current stabilizes. 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 realizes that there has been a reduction in current. It doesn’t like this and tries to keep it constant, so it’s going to push electrons out and try to stabilize it. This will power the light up. Remember, the magnetic field has stored energy from the electrons flowing through it, and it will convert this back into electrical energy to try and stabilize the current flow. But the magnetic field will only exist when the current passes through the wire, and as the current decreases from the resistance of the circuit, the magnetic field collapses until it no longer provides any power.
Okay, that’s it for this video! To continue your learning, check out one of the videos on screen now, and I’ll catch you there for the next lesson. Don’t forget to follow us on social media as well as visit theengineeringmindset.com.
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This version maintains the educational content while removing any informal language or unnecessary details.
Inductor – A component in an electrical circuit that stores energy in a magnetic field when electric current flows through it. – Example sentence: The inductor in the circuit helps to smooth out the fluctuations in the current.
Current – The flow of electric charge through a conductor, typically measured in amperes. – Example sentence: The current flowing through the wire was strong enough to power the light bulb.
Resistance – A measure of how much a material opposes the flow of electric current, usually measured in ohms. – Example sentence: The resistance of the wire determines how much current can pass through it.
Electricity – A form of energy resulting from the existence of charged particles such as electrons or protons, typically used to power devices. – Example sentence: Electricity is essential for running most household appliances.
Magnetic – Relating to or exhibiting magnetism, which is the force exerted by magnets when they attract or repel each other. – Example sentence: The magnetic field around the magnet was strong enough to move the metal filings.
Flow – The movement of electric charge through a conductor, often described in terms of current. – Example sentence: The flow of electricity through the circuit was interrupted when the switch was turned off.
Energy – The capacity to do work or produce change, often seen in forms such as kinetic or potential energy in physics. – Example sentence: The energy stored in the battery was used to power the remote-controlled car.
Pump – A device used to move fluids or gases, often used in engineering to transfer liquids from one place to another. – Example sentence: The water pump was used to circulate coolant through the engine.
Electrons – Negatively charged subatomic particles that flow through conductors to create electric current. – Example sentence: Electrons move through the copper wire, creating an electric current that powers the lamp.
Circuit – A closed loop through which electric current can flow, typically consisting of a power source, conductors, and other components. – Example sentence: The circuit was completed when the switch was turned on, allowing electricity to flow to the light bulb.
