We talked about power, voltage, current and electrical resistance around. Or even how many watts, volts, amps, and ohms a product has, but after all, do you know what each of those really means? Hey engineering lovers, my name is Gustavo Pereira, and a lot of people end up getting confused between the different electrical units and magnitudes that we see around.
We can even hear someone say that the voltage of an equipment is one and its amperage is another. And so, if you are in a circle of friends talking about a subject or trying to explain electrical in a simpler way, ok, but know that both terms are not technically correct and I will explain. Well, the basic components of electricity are relatively easy and logical to understand.
Most electrical terms relate to each other and get along as a harmonious family where they are all correlated and interconnected. But before messing with any electrical wiring in your house or even opening a device and understanding how it works, it is important that you understand and know electrical quantities, their relationships and especially how they work. And for that it's good for you to know the famous Ohm's law, actually the wheel of Ohm's law, where it interconnects all electrical quantities.
And let's start with the famous watt. The watt is a unit of power in the SI system, or the International System of Units, and it represents the amount of energy in joules that is converted, used, or dissipated in an interval of one second. That is, when we say that a device has 300 watts, we are talking about its power, and it means that the device consumes 300 joules of energy per second.
Within Ohms Law, we can calculate power in 3 ways: Multiplying the voltage by the current, squaring the current times its resistance, or dividing the voltage squared by its resistance. Save those names I used in the formulas because I'm going to talk about all of them in this video, ok? For example, if we have a shower head that uses a voltage of 127 volts and has a current of 40 amps, we would expect that shower head to be approximately 5080 watts.
That is, it would have 5080 watts of power. And what is volt? The volt is a unit that represents the electrical voltage, which can also mean the electrical potential difference and is also a unit of the SI system.
When we say that an appliance works on 127 volts, we are saying that it works on the VOLTAGE of 127 volts. A lot of people talk about the term voltage, but for those who are laymen on the subject, that's ok, because the term can be simpler to understand the electrical quantities. But technically for those who know, the term voltage is wrong, and we should always use the term voltage for that.
For that bar talk, it's okay to talk about voltage, now to treat it professionally, use the term voltage, ok? In Brazil, it is common to use the voltage of our domestic electrical networks with 127 volts or 220 volts. It is common for devices that have a lot of power to work with voltages of 220 volts, this is because it has a direct relationship with the current that I will explain shortly.
On ohm's law wheel, voltage can be calculated in 3 ways. Taking the square root of the multiplication between the power and the resistance, dividing the power by the current AND multiplying the current by the resistance. That is, that same shower we used in the first example, if we know that it has a power of 5080 watts and we divide it by the current of 40 amps, we will arrive again at the voltage of 127 volts.
It's basically the same formula I used earlier to explain power, but with the reference units in different positions as we apply the math. Then someone comes and says: Oh dotô, what is the amperage of this thing here? This is more of a term than in layman's language, okay, but in technical language, it's wrong.
The ampere is a unit of electrical current in the SI system and it is equivalent to one coulomb per second. The coulomb is a unit of electrical charge also in the SI system. When we say that a device has 10 amps, it means that an electric charge of 10 coulombs per second is carried in the conductors.
And as I said, the ampere is a unit of current, which is often referred to as amperage, but you already know right? To exchange an idea with that friend of yours, it's worth saying amperage, but when you're dealing with an electrical room in a substation, it's better to say current, okay? And again on our ohm's law wheel, the current can be calculated in 3 ways: Dividing the voltage by the resistance, taking the square root of the power divided by the resistance, and also dividing the power by the voltage If we want to know how much current a 100 watt computer using the voltage of 127 volts will carry, we can divide its voltage of 100 watts by the voltage of 127 volts, and so we will have that its current is equal to 0.
78 amps. Knowing the current that a device consumes is very important to even define the wire gauges to be used. That's why normally the wire gauges of a shower or some equipment with a lot of power are usually larger than the wires of a common house socket and even the circuit breakers that are used are different and have values according to the current that will pass .
by the wiring. And finally, we have the famous resistance. Resistance is represented by the Greek letter omega or ohm, and it is used as a measure of electrical resistance also standardized by the SI system.
When we talk about conductors of electricity, it is common to talk about materials such as aluminum and aluminum, and both are good conductors of electricity, but both have specific resistances to the flow of electricity. That is, they have different resistance values. It's as if you imagine a garden hose.
If you use a hose with a small diameter, your flow will be limited by that diameter, and if you change it to a larger diameter, you will increase your flow. And we can correlate resistance with flow, which is how much electrical flux a conductor can carry. A great example of known resistance is the shower resistance, which we change from time to time.
The conductors used in the shower have a very high resistance, that is, they allow a low flow of electricity, and as a result, they suffer from what we call the joule's law, which is the relationship between the heat generated and the electric current that travels in a conductor. As we have a very high resistance in a shower with a very high current, it is to be expected that its power is also very high. And nothing better than talking about resistance and showing it on our ohm's law wheel, and we can calculate the resistance in 3 ways: Dividing the voltage by the current, Dividing the power by the current squared, And squaring the voltage and dividing by potency.
So in our beloved 127 volt shower head with a current of 40 amps, it will have a resistance of 3. 18 ohms. We don't usually see this measurement in our showers, and it's common to see voltage, current and power, but with the formulas, we are able to calculate their resistance as well.
And did you notice how ohm's law and its wheel make our lives easier when it comes to electrical quantities? The physics and mathematics for its use is very simple, you just need to understand its concepts and understanding ohm's law can be one of the most important for you who want to understand about electrical concepts. Did you already know all these formulas and did you know ohm's law?
Leave it here in the comments I want to know. Here on the side there are two videos that you might like too, so click on one of them to check it out. This is your time to like the video, subscribe to the channel and activate notifications on our channel using the bell symbol.
That's it my friends, a big hug and see you in the next video.
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