RL&RC Circuits and Inductors

This lab had the intention to explain to students what an inductor is, does, and how it can be calculated. It also explains the relationship between the resistors and capacitors in a circuit.

RL means that a circuit contain a Resistor and an Inductor that are connected in series or can be connected in parallel. The Resistor has the function to reduce in certain way the amount of current that can pass. This finality has different applications, where one of them is the water portable immersion heater. Since the current that passes through it is at higher values, the resistance that is presented will limited how much passes and that will create some heat that is released to boil water or a liquid. However, the Inductor acts like a "police border". If a circuit the current that passes through it is increasing, the Inductor will "put the current in waiting". This will create a back EMF some of the energy from th current will be storage and it will create a magnetic field. This works accordingly with the Lenz's. When the current within the circuit increases a back EMF, when the current decreases the EMF goes in the same direction as the current. And when the current is decreasing, the inductor will supply the circuit or act like a battery. The energy that was stored in the magnetic field will be converted in a potential voltage, supplying the circuit with additional current flow.

The picture above, related the Gauss's Law for Magnetism and Faraday's Law for Induction to find the mathematical expression for the induction, represented with the letter L and with Henries (H) as its unit. We can see from the picture that L is always positive, even with the EMF being negative.

In this two pictures we can see that a inductor and a resistance connected within the same circuit. The resistance can be found in series or in parallel, but an inductor is found connected in series with a resistance or capacitor. For a RL circuit, a circuit with a resistance and an inductor, the current is the one that will determine how they will behave. For example, if the current through the circuit is constant the inductor will act as a wire, that means that we considered that there is no changing in direction for the current, except the amount of current that passes through since a resistance is present.  It is also importante to know that, the EMF can be either positive or negative. It will be negative when a back EMF is created that is when the increasing current is passing through the inductor. And it will be positive when the current that passes through the inductor in decreasing.