Ohm's Law and other important stuff

I'm equally excited and nervous, and you should be even more so. The time has come to look at Ohm's Law. After reading this post, you'll have the best tool for analyzing and designing circuits, but that will only be if I can explain myself well... Let's give it a try. Before that, a brief comment on the way Ohm's Law is usually taught, since it tortures me inside. Typically, the three quantities (voltage, current, and resistance) are presented in a kind of pyramid or triangle. See for yourself: go to your trusted search engine (But come back here!!!) and search for "Ohm's Law." You'll see a ton of drawings and pyramids. Well, that's all bullshit 💩 . Seriously, I don't understand what drawing it as a pyramid does; it's just adding empty information. Some might argue that it's just to make it easier to remember. That would make sense if the equation were very complex, but come on: V=I*R, it's not that difficult, is it? Humans have the ability to remember such a short equation. I'm more relaxed now; I finally said it. If you're going to join the secret society of electronics, you must swear never to teach Ohm's Law with pyramids. And here we go, let's get to the topic.

Ohm's Law and other important things

In electronics, there are three very important quantities: voltage, current, and resistance. Ohm's Law tells us how they relate. In case you're too lazy to read long texts, here's the equation in its three forms, although it probably won't tell you much:

V = I x R, I=V/R, R=V/I.

Well, if you're reading this blog, you probably like to think and see things in depth, so now let's expand on the topic a bit. The first thing we need to do is understand what voltage and current are. Another way to refer to voltage is with the term "potential difference," which is quite pro and we will see why soon. Okay, I'll cut the crap and start with important concepts.

Electric charge

Electric charge is a property that elements/molecules/isotopes possess. This property is responsible for the electromagnetic force, which, bluntly, is the force that some charges exert on each other (there's enough substance behind this phrase to write several books, so do your own research). They exert force in the same way that you can exert force on an object or another person, or that the Earth exerts on everything (gravity). Charges manifest in two ways, which we've called "positive" (+) and "negative" (-), although we could have called them "A" and "B," or "blue" and "red." For example, magnets also manifest in two ways, and we call them "north" and "south" for historical reasons (think of compasses). The terminology isn't critical; the important thing is that there are two ways in which the phenomenon manifests. Well, you might wonder what the difference is between positive and negative charges. Well, there isn't any difference if we consider the charge as something isolated. However, they do modify their behavior in relation to other charges. We've said that charges are responsible for the electromagnetic force, and this, translated into practical terms, means that charges apply a force on each other. Note, this force is exerted by charges, and charges also feel it. Force is a vector magnitude, meaning it has a direction, in addition to its value itself. Well, two charges feel a force in the direction of attraction if they are different (positive with negative), and in the direction of repulsion if they are of the same sign (positive with positive or negative with negative).

In the first part of the series, we discussed conductors and insulators. Now that we know what charges are, we can delve a little deeper into the topic. In a conductor, charges can move freely. Conductors are made of materials whose atoms are arranged in a certain way, allowing easy movement of electrons within the material. In an insulator, the exact opposite occurs.

An important nuance: generally, when we talk about charge, we're referring to net charge. Generally speaking, within a material, positive and negative charges are balanced, and their forces cancel each other out (it's much more complex, but we'll stick with this idea). Net charge tells us about those "excess" charges that generate forces that other "excess" charges can feel. The vast majority of charges are balanced. Net charges are very few in comparison, but they are important! It's the net charge that matters to us in electromagnetic phenomena. I won't write about net charge all the time; I'll talk about charges in general, so don't forget this aspect.

It's worth asking where the charges are within a material. Are they distributed randomly? Equally distributed? Only on the surface? Reflecting on these questions will help you understand the concept of charge. Remember: electric charges generate forces between themselves, on each other. You also know that a force accelerates the entity that receives it, which in this case are also charges. In a conductor, the (net) charges can move freely, so it's expected that the forces that the charges exert on each other will lead to a state of equilibrium in which the charges eventually remain "still" after repelling each other. That is, they maximize the distance between them. This occurs on the surface of the conductor.

From a physical point of view, charges are defined by subatomic elements: the proton and the electron. If an element has the same number of particles of both types, then it is a neutral element. If it has more protons, then it has a net positive charge, and the opposite is true if there is an excess of electrons. Important: a negative charge is not the same as an electron. The electron has negative charge. I mention this because it's common to overuse the language related to this topic (I will, I've warned you!). Charge is measured in units of Coulombs [C], and is usually identified in equations with the letter Q. The letter Q stands for "Quantity" of electricity. A bit tacky, in my opinion, but electronic terminology has its charm. Someday I'll write a post about it, especially the historical one. Returning to the units of charge: you might be wondering, is a Coulomb a lot or a little? Well, for general things of normal sizes, a Coulomb is a looooooot. A proton or electron has 1.60217663 × 10 ^-19 Coulombs. By the way, I used scientific notation. If you're not familiar with it, stop reading this immediately and learn that first.

Although charge is the basis of electricity, paradoxically, it isn't often mentioned when working with electronics. That's because we're interested in charges, yes, but even more so when they move. That's exactly what we're going to look at.

The current

Now that you know what charges are, we can think in some detail about current. In previous posts, we've used the term without dwelling on it too much, so it's time. Current is, quite simply, charges that move. You can see I've fallen into the abuse of language I mentioned earlier. What moves isn't charge, but charged particles, typically electrons. In the usual terminology used in electronics, the electrons that participate in the current are called charge carriers. There are other charge carriers besides electrons, and not all electrons are charge carriers, but don't worry about this for now, as we'll cover it when we talk about semiconductors. It's worth pausing here for a moment because there are two very common confusions among electronics enthusiasts.

Let's start with the first one: if we say that current is moving charges, it's clear that they have to move somewhere. Let's continue with the light bulb circuit we saw in the previous part of this series. Current moves in a closed loop, yes, but it does so clockwise, or counterclockwise? Well, 18th-century scientists asked themselves a similar question. At that time, they didn't know that charge carriers were electrons. Well, more accurately, they didn't know what an electron or an atom is (note: Do we know this well now? If there's a physicist in the room, please comment). So, they assumed that charge carriers were positive charges ("protons," but be careful because they didn't know what a proton is) and that these charge carriers emerge from the positive terminal (they repel each other from the positive terminal because they have charges of the same sign) and move toward the negative terminal, because they are attracted. This hypothesis was generally followed, that is, assuming that current emerges from the positive terminal and flows to the negative terminal. And so far, so good, but there's a problem: It's all wrong! The hypothesis they used is incorrect, and what happens is that the charge carriers are the electrons, which move from the negative terminal to the positive terminal. However, by the time they realized it (many years later), the idea that the current flowed from positive to negative had already spread. What is the consequence of this error? None. How is that possible? Because, in a circuit, we can invent the direction of the current, and the results won't change. If you don't believe me, we'll see it later with an example. So, the "erroneous" direction is called the conventional current direction , while the other is the direction of the electrons. Everyone who isn't crazy uses the conventional direction. Take a look at the following figure in case the explanation wasn't entirely clear.

The second common misunderstanding is that electrons move around the circuit. Before we begin, a warning: the theories that explain how electrons move around materials are very complex. Fortunately, they offer nothing to the average electronics expert when working on their projects. Let's go back to the confusion. If we say that current exists in a closed circuit, and we also say that current is moving charges, we can conclude that electrons move in circles around the circuit. No, that's false (in reality, they do move a little, and very slowly, but we won't get into that now). It's not necessary for the elements to move to propagate a movement. Think, for example, of a chain of domino pieces falling. There is movement, but the dominoes don't advance with that movement; they stay still. Obviously, what happens at the subatomic level has nothing to do with domino pieces; I'm just giving it as an example so you can see that particles don't need to move for energy to flow. You can think of electrons as influencing each other, and that influence propagates very quickly through the material.

Okay, after reading the last two paragraphs, you can forget about them. You'll never need that info again. This next bit is important: current is measured in amperes [A]. An ampere is one coulomb of charge passing through a section of a section for one second [C/s]. The letter used to identify current is I, for intensity. The words "intensity" and "current" are often used interchangeably to refer to the same thing. Finally! Now you know what current is. Just one last note: the verb used for current is "to pass." Current passes through a component/wire/whatever. A question you might be asking yourself is: Why would the charges start moving? Read on.

The Voltage

The concept of voltage is quite complex, so we'll start with a simple definition and then go a little deeper. Voltage, also called electric potential difference, is the work required to move one unit of electric charge between two points in an electric field. At a intuitive level, you can understand that it's a magnitude that tells us how eager the charges are to move around the circuit. I admit this definition isn't very rigorous, but it's practical. Let's dive a little deeper into the topic. If you recall, we said that charges exert forces (attraction or repulsion) on each other. When a force is exerted on something (be it a charge, a ball, a chair, or anything else), that something accelerates. However, you don't see charges spontaneously moving back and forth. That's because the forces are (almost) perfectly balanced. They are because a ton of charges exert forces on each other in every direction and compensate for each other. It's like if I'm pushing you from the front, but someone's pushing you from behind. If we do it with the same force, you won't move. The areas of space where the force generated by charges can be felt constitute the electric field . Get ready, because the important part is coming: activate your brain.

The charges and the field they generate are there, motionless (what's called a static field ). In this electric field, there are forces generated by the charges, no matter what they are. Well, voltage is the work that must be done on a charge to move it from one point to another in space within this electric field full of forces. I used the word " work," which you might remember from high-school physics. Work is a force applied over a distance. In this case, it's the force of the field applied to the charge, and as a result of this force, the charge moves. It's also worth reflecting a little more on the subject. Let's do it, this time, thinking in terms of energy . Remember that energy is the capacity to do work. When an object is in a field (in this case, electric, but the same happens in gravitational fields), it has a certain potential energy . You can understand potential energy as something that isn't manifesting itself, but is available to do so. Quick example: imagine you're holding a stone in your hand. The stone is still, right? But what happens if you open your hand? Obviously, it falls. When it falls, it transforms the potential energy it had due to being at a certain height into kinetic energy (movement). In other words, the stone-Earth system had stored energy ready to be transformed into another. We have an analogous situation in the electric field. There is a field with forces. If we leave a charged object at a point in the field, it will experience a force of attraction or repulsion, depending on the sign of its charge. That charged object, therefore, has a certain potential energy. Well, if that object, instead of being an object, were a single unit of charge, we would say it has an electric potential . This potential depends on its location within the electric field (in gravitational terms, you can probably guess that a stone held 5 cm off the ground doesn't have the same potential energy as if you held it 100 m high). In a way, you can imagine that an electric potential field exists , although I'm not sure if this is philosophy or physics. But, to avoid confusion and return to the origin, that is, to answer the question of what voltage is. Well, it's the difference between the electric potential of two points in the electric field. Tadaaa. Voltage uses units of Volts [V], which are derived from work divided by charge, whose units would be Joules per Coulomb [J/C].

Take a moment to imagine a situation in which we move a charge between two specific points in space. The charge being moved is affected by the forces of all the other charges. Look at the following image (drawing isn't my strongest skill 😂):

At the bottom left, there is a green region representing several charges placed together. Since it has an arbitrary shape, the field forces (represented by the black arrows) do not point anywhere in particular. On the right, there is a second charge moving through the field. This charge is subject to the field forces, so as it follows the indicated path, it does work (or the field does it over it?). We call this work, the potential difference, or voltage, and it is denoted as “∆V,” although it is often simplified to simply “V.” The symbol delta ∆, in equations, often refers to concepts such as “variation,” “increase,” or “difference.” The “V” refers to “voltage.” In the previous image, voltage is the difference in electric potential between point “a” and point “b.” For example, suppose the potential at “a” is 10 V, and the potential at “b” is 11 V. Well, the voltage, or potential difference between "a" and "b" is 1 V. In electronics, potential itself doesn't matter to us. What we're interested in is knowing the potential difference between two points because that determines the behavior of the charge between those two points.

Let's bring the concept down to earth with something familiar: the electrical outlets in your home. Between one hole and the other, there's 220V. Note, it's not that one hole has 0V and the other 220V. It could very well be 1000V in one, and 1220V in the other; or 7V in one, and 227V in the other; or -420V in one, and -200V in the other. It makes exactly the same difference. Now, for the sake of economy and to simplify equations, we assume that the potential at some point in the circuit is 0V. We call that point ground , or earth. You've probably heard those words before, and now you know exactly what they refer to.

When drawing circuits, it's important to indicate where the 0V reference is. If we don't, it's difficult to communicate with others because everyone might think the 0V is somewhere different. Typically, although not required, it's assumed that ground is connected to the negative terminal of some voltage source. However, I want to reinforce the idea that there isn't actually a 0V at ground. This is a convention to facilitate calculations and communication. In this sense, the following two circuits are identical, although one looks much simpler.

The circuit on the left has the ground symbol drawn on the negative terminal of the voltage source, which for us is a plug that guarantees a difference of 220V between its holes. This implies that the positive terminal has 220V relative to ground . In the drawing on the right, I've drawn the ground between the two light bulbs. Why would anyone do this? Because they're crazy. However, now it helps us reinforce the concept of potential difference. In the circuit on the right, we agreed that the 0V point is between the light bulbs. Now, in this new convention, the positive terminal of the voltage source is at 110V, while the negative terminal is at -110V . If you notice, the difference between the positive and negative terminals is still 220V. That 220V difference will generate the same current regardless of where I draw the ground.

You'll have noticed that I've drawn a "110V" icon near each bulb with a "+" and a "-". This is how the voltage drops are indicated . The verb "to drop" is used. Very important: never in your life say the voltage " passes". It's the most important rule of electronics!!! Back to voltage drops. I've written 110V because we're assuming the bulbs are the same. So, if the socket guarantees a difference of 220V between the holes, and I have two identical bulbs, each bulb corresponds to 110V. But what if the bulbs were different? Wait right there, don't move! That's a very correct question, and we'll answer it using Ohm's Law.

Electrical power

Another important quantity you should familiarize yourself with is electrical power. The term power is perfectly integrated into everyday language and we use it in various contexts with fairly loose definitions. In electronics, we have to use it precisely, so it's important to have it perfectly defined.

Generally speaking, power is the energy transferred per unit of time. That is, it gives us an idea of the rate at which a given energy is used/transformed. To give an absurd example: imagine I have a medieval wall. My enemy has a catapult and throws stones at the wall. With each stone thrown, energy is transferred to the wall, causing it to move/deform (doing work) and also causing noise and vibrations. Let's suppose that wall breaks after 10 stone impacts because the transferred energy will be enough to break it. Well, power puts the time it takes for that event to occur into perspective. If the enemy throws 10 stones at me in an hour, the power of his catapult will be low. On the other hand, if he throws 10 stones at me in a minute, the power of his catapult is very high. Note that both catapults throw 10 stones (they transfer the same energy) and break the wall equally, but the time in which they do so changes (one hour vs. one minute).

Fantastic, but this isn't a medieval siege site, so let's use the idea from the previous paragraph but apply it to electronics. In the previous sections of the post, we've talked about charge, current, and voltage. These quantities are obviously related to power, although it's not entirely trivial. Remember, power is the rate of energy use. We have to arrive at that definition from our electrical quantities. Let's review basic concepts very quickly. Electrical charges generate an electric field with forces of attraction or repulsion acting on other charges. Voltage (or potential difference) is the work required to move a charge in a given electric field. Work is the transfer of energy through the application of a force over a distance. Current is the amount of charge that passes through a given location in a given time. As you can see, reviewing the definitions brought up the topics of energy, time, and work, just as in the catapult example. Electrical power is the product of voltage and current, that is, P = V * I. The voltage term “V” tells us the work (energy transfer) per unit of charge, while the current term “I” gives us the rate at which this occurs, that is, the charges per unit of time passing through a location. Power is measured in Watts [W], which is a simplification of Joules per second [J/s], i.e., energy per unit of time. If you’re not brain-fried yet, you might be a little shocked. We did V * I, which is measured in Volts and Amps, and we ended with Joules per second… Sounds suspicious. However, it’s all 100% legal. Remember the definitions of voltage and current and you’ll see that it makes sense that Volts equals Joules divided by Coulombs (J/C), and Amps equals Coulombs divided by seconds (C/s), so it all fits together. Phew, what a dense paragraph!

But, why am I giving you all this info? Why is it important to control power in electronics? These are quite reasonable questions. Well, there are several reasons. The first is that all circuits need to consume energy at a certain rate (i.e., they need power) to function. Therefore, our power sources must be appropriately sized for our circuits. For example, the power supply of the PC you're reading this on is sized to handle the power required by the rest of its components. Another reason is that power is a quantity that can be "exchanged" in different systems. For example, we can convert electrical power into mechanical power and vice versa. That's what electric motors and generators do. Think of an electric car. For it to work, power must be "brought" from power plants, which can be of various types, to the car's engine. Depending on the type of power plant, power of some type is converted into electrical power, that is, into voltage and current, which is distributed through the electrical grid to the electric car in question. These processes aren't perfect, and power is always "lost" along the way in the form of heat. The metric we use to refer to how well a system manages power is efficiency, which is basically the ratio of the power available for final consumption to the initial power.

One last terminological question about potency. We sometimes give potency names. I'll tell you the most common ones in case you see them around. However, disclaimer: there are many abuses of language with these concepts. They may generate some controversy or ways of understanding them.

• Generated power refers to the electrical energy produced by a source, such as a generator or battery, per unit of time. It represents the amount of energy available to the system.
• Delivered power refers to the energy (per unit of time) that one component or system supplies to another in an electrical circuit.
• Dissipated power refers to the energy (per unit of time) converted into heat or lost in a component, such as a resistor, due to phenomena such as electrical resistance or inefficiencies.
• Power consumption refers to the electrical energy (per unit of time) used by devices or loads to perform useful work, such as lighting, moving, or powering electronic circuits, per unit of time.

And now, I'll let you live and move on to other things.

Ohm's Law

It's time to make yourself a cup of coffee, a glass of wine, or a pint of beer because you deserve to enjoy the moment. You've reached the section where we'll cover Ohm's Law, and you've done so by learning the concepts that are part of it.

In reality, charge, voltage, and current are much more complex concepts (but much more so) than what we've seen here, but they'll serve us well for what we'll need. I'm telling you this so you can do a little more research at some point in the future.

We've been talking about current, which, briefly, is moving charges, and we've also talked about voltage, which is the "effort" charges have to make to move. These two quantities deal with the behavior of electrical charges. One might wonder if there are predictable relationships between voltage and current. For example, if I know a voltage (or potential difference) between two points, can I know what current there will be? Or, if there's a current passing through a component, can I know what voltage will drop across the component? These and similar questions were asked by many people during the 18th century. With modern instruments, "discovering" the relationship between voltage and current would be relatively simple, but at the time they had many limitations. To give you an idea, the first rudimentary current meters were invented around 1820. Before that, they measured current by putting their bodies in the circuit and electrocuting themselves. A lot of pain = a lot of current. That was truly hardcore science. Today, if you use interns to measure current, you'll probably end up in jail... I guess things have gotten better. Okay, I'll stop talking nonsense.

Those who researched electricity back then, suspected that voltage and current must be related, but they didn't know how and what factors could influence that relationship. They couldn't make much progress without precise measurements, so the work didn't progress much until two key elements were invented: the thermocouple and the galvanometer. We won't go into much detail about the operating principles of these two inventions (which are still in use), but I recommend you do some research, as they are quite interesting. I'll just give you some very basic notions to connect with Ohm's Law.

A thermocouple is a transducer that relates temperature and voltage. "Transducer" is a bit of a peculiar word, so you may not have heard it before. Simply put, it's something that transforms energy from one form to another. Your life is full of transducers. For example, a loudspeaker converts electrical energy into acoustic energy. A microphone does the opposite. An electric motor transforms between electricity and motion. Well, going back to the thermocouple, we have a relationship between temperature and electricity. Specifically, there is a relationship between temperature and voltage. If you want to investigate how a thermocouple works, investigate the thermoelectric effect. The point is that, with a thermocouple, you can generate voltage, and this voltage depends on temperature. Before the invention of the thermocouple, Georg Ohm, today's protagonist, couldn't accurately measure or generate voltages, but he could heat things and measure temperatures. So, when the thermocouple was invented, he was very excited and started investigating.

The second key invention, the galvanometer, allows current to be measured. It's a rather sophisticated kind of compass. A compass, as you know, is a device with a magnetized needle. This needle aligns with the Earth's magnetic field lines. The Earth's magnetic field is (to summarize) a natural effect. However, magnetic fields can also be produced at will via electric currents. In a future post, we'll talk about the relationship between the electric and magnetic fields (it's sooo important), but I can't get into that topic now because it would derail the train. The key point is that electric current generates a magnetic field. So, briefly, how does a galvanometer work? Well, this instrument has a permanent magnet (like the ones on your refrigerator) inside that causes a magnetized needle to point in a certain direction. The galvanometer also has a coil of conductive wire inside. This coil is connected in series with the circuit, so the current of the circuit to be measured passes through the galvanometer. When current passes through the coil and a field is generated, the aforementioned magnetic needle changes direction, as it is acted upon by two forces: the magnetic field generated by the permanent magnet, but now also the magnetic field generated by the current passing through the coil. Depending on the current passing through, it changes direction to a greater or lesser extent, allowing currents to be measured.

In the image above, you can see the elements that make up this invention. Let's say the magnet forces the needle to be in the center, but when current passes through the coil, a force rotates the cylinder inside the magnet to the right, in the case of currents in one direction, or to the left for currents in the opposite direction. The forces of the permanent magnet and those generated by the current balance each other in one position or another depending on the magnitude of the current. It's a pretty neat invention by the standards of the time.

With the thermocouple and the galvanometer, Georg Ohm was very happy experimenting. He could finally apply controlled voltages through the thermocouple, since he could control the temperature, and he could also measure the currents generated. Therefore, after various observations, he could confidently establish a relationship between voltage and current. What he did was connect the ends of the thermocouple (where the potential difference associated with the temperature difference occurs) with copper wires of different lengths and thicknesses. For each copper wire he connected, he asked himself the following questions:

• What is the current passing through this copper wire?
• If the wire is longer, current is higher or lower?
• If the wire is thicker, current is higher or lower?

After measuring several wires, recording the results, and plotting them on a graph, you should have obtained something similar to the following:

On the vertical axis we have current. On the horizontal axis, the length of the wire. I have drawn the traces resulting from experimenting with wires of various thicknesses. What he observed was that, for a constant voltage and wires of a specific material, the current depended on two factors: the length and thickness of the wire used. If the wire was longer, the current was lower. If the wire was thinner, the current was also lower. The opposite happened for shorter and thicker wires. Furthermore, he must have also seen that if he changed the wire material, the currents he measured changed, but followed the same pattern: long, thin wire à little current; thick, short wire à high current. He called this characteristic of each of the wires (or would have called it if he spoke in the terms we use today) resistance . The unit used to measure resistance is the Ohm, represented by the capital letter omega [Ω].

His work on characterizing the current based on what he connected (material, thickness, length) to the thermocouple provided him with all the ingredients he needed to study the relationship between voltage and current; he was now very close. Recall that he had conducted the experiments with a constant voltage using a thermocouple at a controlled temperature. Now the question was: if he repeated the experiments, but with different voltages , what might happen? He thought this question was very difficult to answer without having a full understanding of the relationship between the current and the material used to close the circuit, since any observation could be attributed to multiple causes. However, that was no longer the case, because Georg Ohm was perfectly familiar with the behavior of currents based on the characteristics of the wires. And, since he knew this perfectly, any observation could be attributed to variations in voltage . So, let's get to work, and repeat the experiment varying the voltage. To keep things simple, let's assume he tried three wires of a known length and material, but different thicknesses. What did he observe when he did this?

On the vertical axis we have the current, and on the horizontal axis the voltage. The graph shows a very simple relationship between voltage and current. Note that, for any wire, the current increases proportionally to the voltage. For example, for a fine wire, if the circuit is stimulated with 10 [V], the current is 5 [A]. If it is stimulated with twice that amount, that is, 20 [V], the current also doubles, 10 [A]. The relationship between voltage and current for a fine wire is 2 Volts for every Ampere. For other types of wire, there will be a different relationship, but the proportionality is maintained. And what exactly is this relationship? The resistance [Ω] we were talking about a few paragraphs above! This simple relationship may seem intuitive now, but it wasn't the case at the time. In fact, around 1820 there was a fairly general consensus that voltage had no influence on current, and Ohm's work was heavily criticized. It even caused him several unpleasant surprises in his life, but we'll talk about that another day. It took several years before Ohm's Law became widely accepted. By the way, I just noticed that I haven't even included the equation. Now you can understand it properly:

$V = I \cdot R$

$I = \frac{V}{R}$

$R = \frac{V}{I}$

The equation can be found in three forms, which are actually the same thing manipulated algebraically. One form or another is necessary depending on what we want to calculate. By the way, on this page you have an Ohm's Law calculator to save you from doing the calculations by hand.

And so, we come to the end of the conceptual part of Ohm's Law. It's been a bit longer than I had planned. In fact, so much so, that I'm saving part of it for the next article. We'll talk about the basic components of circuits (surprise, in real life, electronics professionals don't talk about plugs or light bulbs 😅) and we'll use Ohm's Law in practice.

Congratulations on your effort to read; these days, it's becoming increasingly difficult. I hope you've learned a little. If anything is confusing or seems incorrect, please leave a comment. Other users and I can learn a lot from you too.