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PART 1 ELECTRICITY - Contenido educativo

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Subido el 30 de enero de 2023 por Beatriz T.

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Electric and elecctronics circuits. Electrical Variables. Ohm's law.
based on "Technology and digitalisation" Ed. Donostiarra

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This unit is basic electricity and electronics. 00:00:00
As we have studied all these years, this is the concept of atoms. 00:00:04
They are formed by protons that are in the nucleus with positive charge and neutrons that don't have charge at all. 00:00:10
Electrons with a negative charge, they are floating in clouds around the nucleus. 00:00:20
In a balanced atom, the number of protons is equal to the number of electrons. 00:00:30
Due to the forces of attraction and repulsion, these particles are balanced. 00:00:38
What happens? There are certain types of atoms that are called metals, in which these electrons are so far away from the nucleus, because this is similar as the stars, sorry, as planets that are making orbits, that are orbiting around the star. 00:00:45
When this electron or planet is really far from the nucleus, then there is a possibility in which another atom can attract with a bigger force these electrons, so these electrons start jumping from one atom to another. 00:01:05
This is called electricity. This transfer of charge is the electrical current and is produced, as I said, in conductive materials that are called metals. 00:01:28
Conductive materials transmit electricity and electric circuits is the path they use to allow this electrical current. 00:01:42
Here you can see the difference between analog electronics and digital electronics. 00:01:54
In analog electronics, we study systems in which current voltage can take any values over time. 00:02:01
That means that, for example, you can have a current of 1.2 or 1.3 amperes or a voltage with decimal figures. 00:02:11
But in digital electronics, we study circuits in which we only take and take discrete values, 00:02:22
normally zeros and ones that represent the open and close of a circuit when you have a switch. 00:02:33
Electronics is a branch of physics that studies the control of the movement of electrons between semiconducting materials. 00:02:46
These materials allow or don't allow the pass of the electricity depending on the circumstances. 00:02:55
Depending on certain factors, they can act as conductors. 00:03:05
The most common semiconducting materials are silicon and germanium. 00:03:13
As I said before, we can divide electronics into two branches, analog and digital. 00:03:20
In electricity, we study the movement of electrons in conducting materials, but in electronics we also use semiconducting materials. 00:03:27
The components in electrical currents are passive, that are resistors and capacitors. 00:03:37
But in electronics we can use passive components and active components as diodes, transistors and integrated circuits. 00:03:45
Let's remember what is the Ohm's law. 00:03:56
the Ohm's law. The Ohm's law is the mathematical expression of the relation between the three 00:03:59
main magnitudes in an electrical circuit that are current, voltage and resistance. Here 00:04:06
you can see the statement that is that the intensity is equal to the voltage divided 00:04:14
by the resistance. What is current? Current is the variable that says how many electrons 00:04:20
are going through a cross section of a conductor the unit in the international system is the ampere 00:04:27
current is represented by a letter i and ampere or amps is represented by a letter 00:04:34
a voltage says what's the difference in the electrical circuit per unit of charge between 00:04:40
two points it can also be named as electric potential difference or volt or drop potential 00:04:48
The unit in the international system is the Volt, or less is the energy that we have in 00:04:56
a circuit. 00:05:03
So if the voltage is zero, we don't have a current at all. 00:05:04
And the resistance is the variable that says the opposition to the electric current is 00:05:09
represented by the letter Ohm. 00:05:14
In this table, you have all the symbols of the units and the symbols of everything and 00:05:17
the sub-multiples and multiples. 00:05:23
first activity consists in trying to solve this exercise in the first 00:05:25
exercise you have to convert these units kilo ohms into ohms so you only have to 00:05:33
multiply by 1000 by 1000 so this is a result the next exercise 3k2 it's 00:05:39
thousand plus two hundred so the result is three two zero zero ohms and the 00:05:53
next one you have 47 kilo ohms so it's 47,000 ohms be careful the next one is 00:06:03
given in milli ohms so you divide it by one thousand is four point seven ohms 00:06:13
5mA is 0.05A, 6A is 6000mA, 2x10³mV is 2V and 3.6kV is 306mA. 00:06:20
We are now calculating basic circuits with the Ohm's law. 00:06:43
First one, calculate a current flowing through this circuit given that the cell is 5 volts and the resistance is 100 ohms. 00:06:51
So the first thing is to write the Ohm's law. 00:06:58
You have to write it. 00:07:03
And then let's see that the missing value of the resistance is the one that I have to calculate. So resistance is equal to the voltage divided by the intensity. 00:07:05
and then just solve it with the resistance will be the value of 5 volts divided by 100 00:07:27
that if you take your calculator sorry it's 5 it is going to be 0.05 and remember that the unit 00:07:37
is ohm. It's ohms. Sorry I cannot write it here. So here you can write that is 0.05 ohms and 00:07:50
well you can write here this is 15 milli ohms but this is not. This is optional. 00:08:08
In this exercise you have to calculate the voltage that the power source of a circuit 00:08:20
with a resistance of 2 kilo ohms must have to allow a current of 2 milli amperes let's make 00:08:25
the calculations again voltage is equal to the intensity by the resistance if you remember the 00:08:33
triangle of the layer of the ohms law and you can remember all the expressions for the ohms law 00:08:40
but in this case we don't have to do anything because the voltage is equal to the intensity 00:08:48
and the resistance that is something that they give us you can do it in to have two options 00:08:52
you know that the intensity is two milliamps that is 0.002 amperes 00:09:00
by um the resistance that is two kilo ohms so this is the operation that you have to do 00:09:09
and the result is going to be if you use your calculator for words another way to do it is 00:09:17
that if you see that two milli amperes and two kilo ohms this milli and kilo they are going to 00:09:26
be simplified because milli means 4, 2, 2 minus 3 and kilo means 2, 2, 2, 3, sorry 2, 10, 2, 3 and milli 00:09:39
10, 2 minus 3, this milli and kilo are going to be simplified and the result is 4 by 4, that is 4 00:09:53
words so your result here is four words now you are going to do exercises from part one 00:10:02
Autor/es:
BEATRIZ TORREJON
Subido por:
Beatriz T.
Licencia:
Reconocimiento - No comercial
Visualizaciones:
6
Fecha:
30 de enero de 2023 - 16:04
Visibilidad:
Público
Centro:
IES CERVANTES
Duración:
10′ 11″
Relación de aspecto:
1.78:1
Resolución:
852x480 píxeles
Tamaño:
43.28 MBytes

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