Menu

Electricidad Basica 1 curso gratis

0 Comment


Welcome, my name’s Daniel Paez. In this opportunity I’m going to talk about basic electricity. We’re doing it in a visual way using the theory. But sometimes being as informal as possible. This will not be a master class in electricity,
for people looking for that kind of information there is much information about it,
there is a lot of theory on the web. I will try to transmit a summary of all
that information, a summary of all that theory. A summary that will serve as a starting point to face topics like series circuit, parallel circuits, alternating current, continuous current, resistance, impedance. Anyway, all the topics that are of interest for
technicians, topics that will make repairs easier, topics that will take us to a better
understanding of the function of different equipments. In future classes I’ll teach you how to read circuits, how to detect failure in measuring, using a multimeter, to make live tests and other interesting things. Like I told you, this chat is aimed at technicians. In general my chats are aimed at them. This one in particular is aimed at
technicians that don’t master electricity, technicians that have the mechanical theory but lack the electricity side, or technicians that know in
practice but need to reinforce some electricity concepts. Nothing else for me to do than to welcome you. Welcome colleagues, and welcome the public in general. Let’s start, let’s see the topics that we’ll discuss. We’re starting with the basics. we’ll define electricity. We’ll discuss the interaction of positive and
negative charges. We’ll talk about the abilities of the electron. We’ll talk about positive and negative poles, conductors, insulators, elemental electrical circuit, We’ll make an analogy with an hydraulic circuit, we’ll talk about the magnitudes of
electricity that are used the most, the flow of current, And to finish we’ll measure a circuit. What’s electricity? Electricity is a phenomenon that has
to do with the interaction of 2 particles. More precisely the interaction that happens between these 2 particles. These particles are the proton and the electron. And is thanks to this attraction,
thanks to the energy between them, and with energy I’m referring to this, the
attraction between the proton and the electron. I mean, if we would like to define electricity fast, we could define it as it is the force of attraction that
happens between the protons and the electrons. That would be the short definition of electricity. Like I said it’s thanks to this energy that a series of phenomenons happen letting us have the use of electricity, so we can watch tv, turn on a light, use the mobile. If it wasn’t for this attraction between the
proton and the electron there would be no electricity. They had signs assigned, the proton a positive sign, and the electron a negative sign, so from
now on we’ll address them through their sign. And let’s talk a little without too much theory that these particles, the electron and the proton are in all matter. Let’s define matter: matter is
everything that has a place in space. Matter is the water, the air, the earth, a piece of paper, a metal bar, a needle, the human body. Anyway, matter is everything
you can imagine that has a place in space. So we could say, that protons and electrons are everywhere, it could be said that
we are surrounded by protons and electrons. We could even say we are made by protons and electrons. That will be it in theory, if you’re more interested there’s more information on the web, you
can investigate What’s matter? What’s a molecule? What’s an atom? What’s it made of? What’s an ion? What’s the valence shell?, so much information in the web there is much more theory that’s so clear.
But this chat pretends to me more practical just like we technicians like. So we won’t go further, we won’t go
into the origin of the proton and the electron. Well, we know that between the electron and the
proton there is an interaction, there is an energy between them from attraction. So we could say that between opposite charges there is a force of attraction, let’s see
what happens when the charges are from the same sign. Well, let’s draw near a proton to another proton, between them is a force of repulsion. They try to move off. the same if we draw near an electron to another,
there’s a force of repulsion that makes them move off. The word electricity comes from the electron. And this is because of the
particularity of the electron over the proton. The electron can move. You can add and subtract electrons from matter. We can take any matter, from any object and add or subtract electrons. What we can’t add or subtract are the protons, the proton is
part of the matter. so it’s virtually imposible to remove protons from an object. We can add or subtract electrons from an object. In some materials the electron because of its mobility, can move
freely, and in some materials it’s more difficult to move around from one material to another.
Let’s take a bar of metal, of copper for example and we can make the
electrons move around from one side to the other easily. Let’s see this in a graphic to make this easier. Imagine we have, matter, an element, for example a coin, imagine that the object on screen is a coin. And the coin in its natural state is neutral. What does it mean?
It means that electrically it’s neutral because the quantity of protons and electrons is the same. If the electron and the proton has an
electrical charge, when they are in the same quantity we can say this coin is neutral, because it has been neutralized. All that energy that the protons and
the electrons has is neutralized between them. And that coin is in it’s neutral state, it has no electrical charge. If we put another coin in a neutral state,
it has no effect because both are neutralized. As we said, we can take our the electrons from objects, so we are going
to extract electrons from this coin. If we remove from this coin, let’s say 4 electrons we will have a positive charged coin And we have a coin with 4 extra protons. Look that we are talking of the same
coin, in the 2 cases we have 8 protons, but the second one it’s charged positively +4 because it’s missing electrons. The same happens if we add electrons. Here we have the same coin with 8 protons, but we add 6 electrons more. In this case this coin is charged negatively by -6. We commented that in some materials electrons can flow easier from one side to the other of the material,
inside the material, and in others is more difficult. These materials are separated in 2 big groups.
They are conductors and insulators. Inside the conductors we have in
general metals like gold, silver, bronze, iron, copper, aluminum, zinc. The insulator materials are: to name a few glass, porcelain, mica, plastics, air, distilled water. So in summary conductors materials are where the electrons can move easier, we can make
the electron go form one side of the material to the other and the insulator materials can’t,
it’s harder to achieve. Let’s see the use we can give to these conductor materials. For example, if we have a positive pole and a negative pole. Imagine these coins that we’ve been using. We have a negative pole where we have an excess of electrons,
and a positive pole were we are missing electrons, because we have excess protons. If we take these 2 poles and put
them together through a conductor material since through conductors materials electrons can move freely there will be an electron current, a flow of electrons, a
circulation of electrons, that will circulate from left to right. From the negative pole to the positive one, one quantity of electrons, to neutralize, to equal, so it’s balances the charge, so it has the same charge of electrons and protons, or at least be equal, that they
have in excess or are missing the same quantity of electrons in the 2 poles, they’ll try to neutralize themselves. This happens because we are using a conductor material.
If instead of putting together these 2 poles with a piece of metal, we use a plastic, this electrical current will not generate, because the electrons in the insulator
materials, the electrons in plastic, in all insulator materials it’s very difficult to move. So there will be no circulation,
there won’t be that current circulation. This circulation of electrons is called electrical current. And thanks to this phenomenon, thanks to
electrical current, thanks to the circulation of electrons, we can use this thing called electricity. 99.9% of electrical appliances or electronics work through this phenomenom and it’s called electrical current, through this circulation, of moving electrones is that a mobile works, a watch that has a battery works, your laptop, a lamp, a blender, all electrical appliances. Like we said, only 99.9% of appliances work with the circulation of electrical
current, from the movement of electrons. There is a very small percentage, I would dare say about 0.1% of devices that don’t need this
circulation, they don’t need that the electron moves, to circulate. These devices work through static electricity. And for example would be a electrostatic cabins.
These cabins work only through the principal of
attraction that is between negative charges and positive ones, they do not need electrons to circulate. This is how they work:
they introduce an object for painting that’s charged positively, so it’s missing electrons, they place it in a cloud, in a cloud of resins and pigments, that’s charged negatively, so this cloud
adheres evenly to the surface to be painted. This piece when it has all the paint, adhered is taken into an oven, where the resins cook and finish
the process of adhering to the surface. This was an example of static
electricity, now we’re moving on to dynamic electricity, the one we’re interested in. The one that has to do with
electrical current, the circulation of electrons. The one that makes 99.9% of the
appliances and devices we’ll find work. For it, to see the use of the electrical current we’ll continue with this graphic. Very similar to the one we had on screen, we’re
cutting this conductor and place a device in the middle. Here we have the same graphic,
where we cut the conductor and placed a device which can be a lamp, a resistance. Let’s imagine this is a resistance. The resistance is a conductor, this
one we have here, let’s imagine is a cable. A piece of copper. It’s a conductor that allows us to pass
electrons, but it’s very thin, it has a measurement that’s smaller. Since it’s thin, it will be an
obstacles when the electrons want to pass. Let’s see it graphically.
We have a conductor, we have a resistance, it’s smaller in size, and the conductor that takes the electricity to the
other pole, the electrons to the other pole. Here come the electrons, with determined force, a determined energy, and they find a narrow road, where to pass they have to make
friction between them, where they have to go through in a tight way. They find this obstacle, this is a
resistance, an obstacle in the electrical current. And when they go through the
resistance, when they go through tight, they will lose speed, they’ll go slower, and they’ll generate heat,
they’ll generate heat on the resistance. This is one of the uses of energy, from the electrical current, from the circulation of electrons. It generates heat, through a resistance and
this friction is because of the electrons going through a conductor which is
thinner than the one it’s feeding them. A lamp is something similar,
I would say it’s the same. The lamp, it’s a resistance, it’s a even more thin conductor. It’s prepared to resist high temperatures. What happens is that friction is bigger, and the element, the filament turns red, to a
point that turns incandescent and generates light. So if we run electricity
through a resistance, it generates heat, If we run electricity through a
filament of a lamp it generates light. If we run electricity through an engine, it will generate an intermediate
effect that’s electromagnetism, that will make the engine spin, that will make the engine work. If we circulate electricity through a speaker, at a rhythm, in a determined way, it will also generate an intermediate effect
that’s electromagnetism, that will interact with a magnet. This will generate movement to a cone and it will make sound. In definite, dynamic electricity, has to do with the circulation of
electrons through a device, and it’s what makes them work. Let’s make a summary,
going through all this information. And let’s start by saying that electricity is an energy that has it’s origins in the
attraction of 2 sub-atomic particles. We mean by sub-atomic, that these 2
particles are inside the atom, 2 very small particles. One of these 2 particles, the
electron, can move between conductor materials, and the electron, can be added and subtracted from matter. So you can add or subtract electrons to any object you want. This way we can generate objects with positive charges when you remove electrons. And you can create objects with
negative electric charge if you add electrons. When these objects with charge
are related, we can talk about poles. For example, a battery has a positive pole and a negative pole. And for last, 99.9% of appliances and devices
work through the circulation of electrons. Through electrical current. This concept, is very basic, it’s very
simple, and is important to keep in mind. That to make a device work, we need to have circulation of current, it’s not enough to have potential, a electricity potential difference, we need to have the circulation of current so a device to work. If we understood these points, we can move forward. Let’s start with a basic circuit. A real electrical circuit. Here we have, a battery, a switch, a device or charge. Let’s see the function of each
of these 3 devices in the circuit. The device or charge would be what we want to work with the electric energy, it can be a lamp, an engine, a resistance, and I want to be clear about a
term that I’m using, the word charge. We were just talking about
electrical negative energy, an electric charge that’s positive, we said that the coin, going back to the coin example. Once we add electrons, we carried
electrons, just like we carry a package in a vehicle, when we have a
package in a truck, we’re adding something. We grabbed the coin and we added electrons, we charged the coin with electrons, then we charged it
negatively then that coin had a negative charge. When we wanted to charge it in a
positive way, since we can’t add protons. Because the idea would be to
add protons, but since we could not. We had a reality, to remove the charge,
to subtract electrons, but in the end we had a coin with positive charge,
a coin that has excess in protons. Then, we referred electrical charge to an object that has excess of electrons, or was missing
electrons, an object that had a positive or negative charge. We’ll use it from now on this word, the term charge. We’re using the word charge to refer to an object that we added a circuit, that we are charging through a circuit,
that we’re adding things it didn’t have. We’re generating a load to this
circuit, we’re generating an electric consumption. If we say that this circuit is without
charge, it means that it’s not connected to an output. When we say that a circuit is with a charge. It means that the circuit is
feeding something, it’s making work something. Well, now that that’s clear, then let’s use the term charge. Now let’s go with the switch. The switch has the function to interrupt the circulation of the current, this black we have
here is the conductor, where the current is consumed. When the switch is closed the current can keep circulating,
when it’s open, the current is interrupted and it stops working. So the switch is the one that will make work or not the lamp or the device we have connected. And for last we have the battery, the
source has a negative pole and a positive pole. Here we can’t use the charged coins like we did before. Because the charge that the coin has will last only an instant, and it won’t be perceptible the effect to the device, the lamp won’t turn on. We need something that will continuously keep a pole with excess of electrons and a pole missing electrons. So we can produce a circulation of
current, and this circulation has to be kept in time. That’s what the sources are used, like batteries, that’s a device that through internal chemical energy keeps continuously the electrons on one side of the poles, on the negative pole and the other side missing electrons, so each time an electron enters the positive pole
automatically because of energy and chemistry. So it takes it and moves it to the negative pole. And keeps us continuously a
positive and negative pole, well until the battery is drained, the chemical energy is consumed inside. Well, We have this clear, these 3 components and what they do. Let’s move on, with the explanation of the circuit, let’s talk
about magnitudes, the tension, the current, the resistance. Let’s make an analogy. Analogy is a term not used very much. But it has a simple meaning and it’s very useful. An analogy is the likeness between different things. And it’s very useful, analogies are used to understand concepts in our minds,
to incorporate ideas that we don’t know looking for likenesses or similarities with things we do
know, to make them easier to understand. So we’re using an analogy to understand an electric circuit,
that it’s not known or hard to understand. Let’s make an analogy with something that we use
normally, and that’s a hydraulic circuit, that’s something that is very similar with an electric circuit. Here we have a hydraulic circuit, where we have a water tank like the ones in our homes, a stopcock and we have something that we don’t have in
our houses, and that’s a hydraulic pump, that’s a hydraulic engine, a turbine, so the passage of water makes the engine spin. so it is the device we are using in this hydraulic circuit. Let’s see the similarities that this hydraulic circuit has with the circuit
we have down on the left, our electrical circuit. And we have the electrons. The electrons that are in the negative pole. That would be the water that’s in the tank
or the liquid that’s in the hydraulic circuit. The electrons in the electrical circuit are the ones moving, the
ones that will circulate in the conductor and go through the device. Here the liquid will flow through
the conductor, the hose and will make work this device that’s the hydraulic engine. We have the negative pole in the
tank, that will be providing the electrones in the electric circuit, that would be the negative pole. Then we have the positive pole,
that would be the one receiving the water, in the electrical circuit the positive pole is the one
that receives the electron after it comes out from the charge. The positive pole receives it. I said that so these poles don’t
discharge we didn’t have a chemical energy. We took continuously the electrons that
the positive pole took to the negative pole. In the hydraulic circuit, we represent that chemical energy through the pump that is continuously recirculating the water or liquid that returns to the receptor tank
and sends it to the receptor tank, to the negative pole. Let’s see where would the battery
be represented in this hydraulic circuit And the battery, we commented before it had 4 components, chemical energy, a
positive pole, a negative pole, and electron. Then, the battery in the hydraulic circuit would be
represented also by 4 components, that would be the provider tank, the receipting tank, the flow of water, and the pump that is in charge to take the
water from the lower tank to the upper tank. let’s see where we have the switch, the switch is the one that opens the
circuit so the electrons will not go in. That would be the stopcock in this
hydraulic circuit that stops the flow of water. If we close the stopcock, we won’t have flow of water. So the device or turbine will not work. We just need to talk about the device, the device in an electric circuit would be the lamp, a resistance, in this hydraulic circuit is represented by the engine,
the hydraulic engine, an engine that’s a device that when water flows inside, it generates movements in the engine. Well, we found 3 components, the battery, the switch, and the charge, we know it’s represented this, electric circuit in the hydraulic circuit. Making a summary the battery would be the
water tanks, the pump that re-circulate the water, the switch that would be the stopcock, and the device or charge that would be the hydraulic engine. Let’s analyze the magnitudes, in an electrical circuit or in a hydraulic circuit we have as a measure the flow of water that circulates in the circuit,
the flow of liquid that circulates in the circuit. And, the hydraulic circuit is measured in liters per
minute, they’re calculated in liters that go through a determined point in the circuit, the
quantity of liters that go through each minute. And that would give us a magnitude, a value, of the quantity of water that’s circulated. In an electric circuit, it’s also measured the electron circulating through a cable. and they’re measured by electric charge by second. It’s called intensity of current, to the
quantity of current that’s going through a cable. It’s represented by the letter I. And its unit is called an ampere.
We can talk about ampere, or milliampere, or microampere. Another magnitude we have is the measure or the value of obstacle that a
device gives the electric current. So, the resistance that it’s giving, the device is
placing a resistance, it’s resisting to the circulation of electrical current. This obstacle is called resistance, it’s represented by the letter R and its unit is the ohms. the abbreviation of ohms, is the symbol of the Greek letter omega. So we have the current that’s measured in amperes, the device that’s measured or is valued as an obstacle that represents the current and valued in ohms. For the last magnitude to measure we have the water pressure, that
we know that the taller it is the tank will give bigger pressure over the pump. With more force the water will go through. And the pressure in the hydraulic circuit is the tension, or the batteries potential difference. Once a battery has more force, once it has a bigger quantity of electrons. The more charge differential between
the poles and more differential potential. When there’s more difference, it’s
said that there’s more tension or voltage. It’s represented with the letter V,
and its unit is volts. When we’re talking about low tension we can talk about minivolt. And if we’re talking about high
tension we can talk about kilovolt. Well, let’s organize all these
magnitudes that we talked about, a summary. And we have the tension or a potential electrical
difference or voltage, we’re talking of the same thing. The source which is the battery, a generator, the outlets in our
homes, is the force that’s giving us the energy, It’s like the electrical
pressure, like the pressure in the hydraulic circuit. The potential difference or the voltage is the force that’s giving us energy. It’s measured in volts, and it’s represented with a V. Intensity, electrical consumption, we are talking about the quantity of electrical charges that go through a conductor or a device. We’re talking about the flow of electrons that’s going through
a conductors or a device. It would be the analogy that we did with the hydraulic circuit, it
would be the liters by seconds that go through the pipes. The intensity is measured by
amperes and it’s represented with the letter I. Resistance and impedance are new terms. they are 2 different things, later we’ll talk about impedance. But in these 2 cases, the resistance an
the impedance, which is telling us the quantity or the obstacle that presents a device the current of electrical current. The more impedance or more resistance
the more the obstacle that presents a device that, has electrical current, of the flow of current. The more impedance the more the
difficulty the electrons have in w higher value. In these 2 cases it’s measured in ohms. When we’re talking about resistance, it’s represented with an R. And if we talk about impedance
it’s represented with the letter Z. Potency, here’s a new term. Well in reality new to our chat,
because we all know this word. The word potency can be found in all
identifying tags in home appliances, in all plates that have tools. Potency is energy or work done in a unit of time. It’s measured in watts and it’s represented with the letter P. This application in theory is not friendly, so let’s explain it in a practical way. And we’re going to say that potency is energy consumed or the energy given by some device, by an appliance. Let’s use a microwave as an example. In the tag of the microwaves in general, they indicate 2 values we have 2 potency values, the potency that consumes and the potency that it gives. A microwave is an appliance that wastes so much energy. It consumes 1300w, and gives a potency of 800W, so it takes 1200w in our home current, or maybe 1300w, and its giving us a work potency of 800w only. So the definition of potency is, the energy consumed or given by a device. About the sense of the current, or which way the electrons move. It’s what we’ve been commenting
until now that’s from negative to positive. It’s the ones that move, from the negative pole to the positive one. This is the physical current, the real current that
happens in an electrical circuit, or in an electronic circuit. People use to think it was the other
way around, from the positive to the negative. For a time, 2 currents were being
used, until people by convention set that for the analysis of the circuit, for calculations, current goes from positive to negative. And that’s most books say today, and we’ll also will use this direction
of circulation, the sense taken by convention that’s a different sense from the real one, and
that says that current goes from positive to negative. So now we know that current is physical, and goes from negative to positive. But the current by convention goes from negative to positive, and these are the names that
they gave them, physical current or electronic current in the books. And conventional current goes from positive to negative. We’ll use the conventional current, so we’ll adapt, to what we’ll find in the majority of
books about the circulation on electrical circuits. Let’s go back to the basic circuit, as you can see I
corrected the sense of current, and the battery with the positive pole, we’re indicating that the
negative goes from positive to negative. Let’s go back to that basic circuit to make some
measures, let’s measure the tension that the battery gives us. Let’s measure the tension that goes to the charge. We can also measure the resistance, the
value of the ohms of resistance to the charge. And let’s measure the circulating current,
the amperage that circulates through a circuit. In this circuit, the amperage will be the same in any point, because the circuit is a closed circuit. And there’s no possibilities that the current
will go to another place, so the current will be the same in any point of the circuit.
What we have to do is to cut in any point, open somewhere the circuit to make this current go through an instrument that lets us measure, and know the amperage that’s going through the circuit. This is animation where we have the same components that we had in the circuit, the battery, the charge, which in this case is a lamp,
a switch. The circuit is the same, here it’s open, the cable normally goes from the battery to the switch what we did is place an multimeter and this is because we need to measure the current that go through this conductor,
so we need that this current, to go through the instrument, so it can measure it. So the current of the battery will go through our
instrument, it will go out and come back to the switch. The ammeter behaves like a short circuit, it behaves like a piece of cable, it presents no obstacle to the flow of current. The current goes in and goes out and the
ammeter made no modification made no obstacle. For the circuit, it’s like it’s not there, it’s like we had a
cable from the battery to the switch like we did until now in the circuits we’ve been working. The voltmeters are placed in parallel, with the device that we want to measure, so to measure voltage it’s not necessary to disconnect anything. You just place the tips of your
tester on the component, over the device we want to measure like we’re doing here, the lamp we placed the voltmeter in parallel, or in the
battery also, we placed the voltmeter in parallel. Support the 2 tips of the voltmeter directly over the battery
or over the lamp without disconnecting anything. Well, let’s start with the animation and in it we can see we have 12v in the battery, in the battery we have 12v. We have 0 amperes because the switch
is open, there’s no current circulation. We have 0v because obviously the switch is open,
it’s not sending the tension from the battery to the lamp. If we close and open the switch,
we’ll see how the lamp turns on, and with the switch close we have a current. We have one current of 2,282 or 2A. That’s circulating through the circuit, it’s
circulating through the lamp, the switch, through the whole circuit. We have a tension, now the 12v tension reached the lamp. And if we open the switch again,
obviously we won’t have current or tension. We have 0 amperes, in the circuit and we don’t have tension. Let’s measure the resistance,
let’s measure the obstacle that presents to the charge. We know that all charges, any device presents an
obstacle for the flow of current, so let’s measure how many ohms the charge¿s obstacles has, which is
the value, the resistance of this charge. But we should use the tester in
ohmmeter, but before we must clear this every time we measure resistance we
have to have the circuit without feed. Now we have the switch open, so it has no feed. And we have to have at least one of the terminals of the device that we want to measure, one of the
terminals has to be in the air, it has to be supporting the circuit. so it doesn’t have to get connection of any kind. In this circuit as you can see has another
component, I mean directly we can measure the resistance. As is it now,let’s measured the resistance. Let’s place the tester in multi function meter and it ells us it has a value of 5.76 ohms, so almost 5.8 ohms of resistance value of the lamp. Let’s see why we commented that
we have to raise a terminal always from the device, we want to measure
the resistance to get a correct measure. And so it’s not connected to any other component. Here we have another circuit that’s similar, what we added is another resistance, another device in parallel with the lamp. And here we have an open switch, so we could measure
the resistance, if we measure now we will get another value. And it will give us a smaller value,
because there are more obstacles, now we have current that will go through the lamp, so when the
ohmmeter measures the obstacle, it will find the lamp, but will also find another way, an alternative way where current can go through so the obstacle will be less,
because now we have current going through 2 ways. Let’s see if it’s true. We have the ohmmeter, and now we have an obstacle of 3 ohms, less obstacles than we had
before of almost 6 ohms, and we only got 2,9 ohms or 3 ohms. So the measure to be right we have to raise one of the terminals of the device we want to read, we have to raise it from the circuit.
let’s do it, let’s disconnect, let’s cut here, and now we can measure the right value of 5.76 ohms, or 6 ohms in the charge. So to make a summary in these last one we talked about measures. Current is measured in series, we have
to open the circuit and place the ammeter in series,
tension or voltage is measured in parallel, nothing to open,
directly place the tip to the device you want to measure. The tip of the tester over the device to measure. And for the resistance we have to raise at
least one of the parts of the device we want to measure and place the tester as a multi function meter ohms,
obviously with the device with no feed. Well, we have finished with the video for today. So I say goodbye with a loving salute. And see you in our next encounter. Daniel Paez
Technical assistance www.paezdaniel.com.ar

Tags: , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , ,

Leave a Reply

Your email address will not be published. Required fields are marked *