Shadowing Practice: Ohms Law Explained - The basics circuit theory - Learn English Speaking with Video
Elige un modo de práctica
Cada modo abre una sala de práctica a pantalla completa.
129 oraciones
Si las oraciones son demasiado cortas o largas, haz clic en Editar para ajustarlas.
1
Hey there guys, Paul here from theengineeringmindset .com.
2
In this video we're going to be looking at Ohm's Law
3
to understand how it works as well as how to use it.
4
There are also two problems at the end of this video for you to test your knowledge
5
and see if you can solve.
6
So what is Ohm's Law?
7
Ohm's Law is the relationship between voltage, current and resistance and how they relate to each other.
8
Ohm's law was developed by a German physicist named George Ohm
9
who undertook many experiments to develop his theory including measuring current by touching live electrical circuits to see how much it hurt.
10
As you might imagine the higher the current the more it hurt.
11
Now there are three formulas we need to use for Ohm's law
12
but we don't actually need to remember these and I'll show you a super easy tip in just a moment.
13
So the three formulas we use for Ohm's law are voltage equals current multiplied by resistance, current equals voltage divided by resistance,
14
and resistance equals voltage divided by current.
15
If that seems like a lot to remember then don't worry because we don't need to remember them.
16
All we need to remember is Ohm's triangle which looks like this.
17
So you just need to remember these three letters in order V, I, R.
18
Then we just write those letters in a triangle with V at the top
19
and we draw a line to separate the letters.
20
In fact you don't even need to remember those
21
because I've made a free PDF guide for you with some worked examples
22
which you can keep on your PC or your mobile and access wherever you need.
23
Links for that can be found in the video description down below.
24
Now all we do when we need to use a formula is cover up the letter we need.
25
So if we want to find the voltage then we write V equals
26
and then we cover up the V in the triangle.
27
That leaves us with I and R so we write I multiplied by which means voltage equals current multiplied by resistance.
28
You can write a little multiplication symbol in the triangle between the two letters if it helps you.
29
Now I know what you're thinking, why is current represented with the letter I and not a C for current,
30
or even a letter A for the unit of ampere?
31
Well the unit of current is the ampere or the amp, and this is named after André Ampere, a French physicist.
32
A couple of hundred years ago he undertook lots of experiments many involved varying the amount of electrical current.
33
So he called this intensity du current or the intensity of current.
34
So when he published his work they took the letter I and it became standard until this day.
35
Now you might also come across formulas where the letter E is used instead of V.
36
The letter E stands for EMF or electromotive force
37
but don't worry about that just stick to using V
38
and substitute V for E if you see it used in Ohm's law questions.
39
Anyway so by covering V we get voltage equals current multiplied by resistance.
40
If we want to find current then we write down I equals
41
and then we cover up the letter I in the triangle.
42
That gives us V and R
43
so as V is above the R like a fraction
44
we can write V divided by R therefore current is equal to voltage divided by resistance.
45
If we want to find resistance then we write down R equals and we cover up R in the triangle.
46
That leaves us with V and I so we write V divided by I
47
which gives us resistance equals voltage divided by current.
48
Let's look at some examples for how to use these formulas.
49
First let's see how we find voltage and how it relates to the other parts.
50
Let's say we have a simple electrical circuit with a battery and a resistor.
51
We don't know what the voltage of the battery is though.
52
The resistor is three ohms and when we connect a multimeter into the circuit, we see that we get a reading of two amps of current.
53
We want to find the voltage, so using ohms triangle, we can cover up the V and that gives us V equals I multiplied by R.
54
We know the current is two amps, so we can write that in, and we know the resistance is three ohms,
55
so we can write that in also.
56
Therefore, two amps multiplied by three ohms gives us six volts.
57
The battery is therefore 6 volts.
58
Now if you want to check your answers for ohms questions then I've built a free calculator on the website.
59
You can just drop your numbers in and it will do the calculation for you.
60
Links for that again in the video description down below.
61
Coming back to the circuit, if we now double the voltage by connecting two 6 volt batteries in series we get 12 volts.
62
If we now connect this to the same circuit the current also doubles from 2 amps to 4 amps.
63
If we double the voltage again to 24 volts, the current will also double to 8 amps.
64
So what's the relationship here?
65
We can see that current is therefore directly proportional to voltage.
66
If we double the voltage, we double the current.
67
Remember voltage is like pressure, is the pushing force in the circuit.
68
It pushes the electrons around the wires
69
and we place things like lamps in the way of these electrons
70
so that they have to flow through these and that causes the lamp to light up.
71
By doubling the voltage we see that the current also doubles,
72
meaning that more electrons are flowing and this occurs as we apply more pressure or more voltage.
73
This is just like if we were to use a bigger water pump then more water will flow.
74
Okay, so what about finding current?
75
Let's say we now have a 3 ohm lamp connected to a 6 volt power supply.
76
To find the current we write down I equals and then we cover up I in the triangle.
77
That gives us V divided by R, so current equals voltage divided by resistance.
78
We know the voltage is 6 volts and the resistance is 3 ohms, so the current is therefore 2 amps.
79
And that's what we see on the multimeter.
80
By the way, if you don't have a multimeter then I highly recommend you get one.
81
It's essential for troubleshooting but also building your essential electrical knowledge.
82
I'll leave some links down below for which one to get and from where.
83
So we saw what happens when we use a resistance of 3 ohms in the circuit.
84
But if we double the resistance to 6 ohms by placing another 3 ohm lamp into the circuit, the current halves to just 1 amp.
85
If we double the resistance again to 12 ohms, the current will half again to 0 .5 amps.
86
We can visually see this because the lamps will become less bright as the current reduces from the increase in resistance.
87
So what's the relationship here?
88
We can see that the current is inversely proportional to the resistance.
89
When we double the resistance the current will decrease by half.
90
If we half the resistance the current will double.
91
Current is the flow of electrons or the flow of free electrons.
92
For us to make this lamp shine we need to push electrons through it.
93
How do we do that?
94
We apply a voltage across the two ends.
95
The voltage will push the electrons.
96
The atoms inside the copper wire have free electrons in their valence shell
97
which means they can very easily move to other copper atoms.
98
They will naturally move to other atoms by themselves
99
but this will be in random directions which is of no use to us.
100
For the lamp to turn on we need lots of electrons to flow in the same direction.
101
When we connect to voltage source
102
we use the pressure of the battery to push the electrons through the circuit all in the same direction.
103
For example to power this 1 .5 ohm resistive lamp with a 1 .5 volt battery requires 1 amp of current.
104
This is equal to 6 ,242 ,000 ,000 electrons passing from the battery
105
and through the lamp every second and if we can achieve this then the lamp will stay at full brightness.
106
If the voltage or current reduces or the resistance of the circuit increases then the lamp will become dimmer.
107
Okay now let's look at finding resistance.
108
Say we have a resistive lamp connected to a 12 volt power supply.
109
We don't know how much resistance is adding to the circuit but we measure the current at 0 .5 amps.
110
To find the resistance we write down R equals and and then we cover up the R in the triangle.
111
We're left with V and I, so resistance equals voltage divided by current.
112
We know the voltage is 12 volts and the current is 0 .5 amps, so 12 divided by 0 .5 gives us 24 ohms of resistance.
113
Resistance is the opposition to the flow of electrons.
114
It tries to prevent electrons from flowing.
115
That's why we use resistors in circuits to reduce the current and protect components such as an LED.
116
If we try to connect an LED directly to a 9V battery, it will blow out because the voltage and the current are too high.
117
But when we add a resistor into the circuit, then these are reduced, so the LED is protected and will shine brightly.
118
So given the circuit, we can increase the current by increasing the voltage, or we can also increase the current by reducing the resistance.
119
We can also reduce the current by increasing the resistance.
120
Okay, time for you to test your skills.
121
Can you solve these problems?
122
I'll leave a link for the answer and the solution in the video description down below.
123
Problem one, let's say we have this lamp which has a resistance of 240 ohms.
124
If we plug this into an outlet in the US which uses 120 volts, what will the current be?
125
Problem two, if I plug the same 240 ohm resistive lamp into an outlet in the UK, we get a current of 0 .958 amps.
126
So what is the voltage being applied here?
127
Okay guys, that's it for this video, but to continue your learning,
128
then check out one of the videos on screen now and I'll catch you there for the next lesson.
129
Don't forget to follow us on Facebook, Twitter, Instagram, LinkedIn, as well as theengineeringmindset .com.
Descargar app
Todo lo que necesitas para hablar con fluidez
Pronunciación con IAEvalúa cada oración
Práctica de IPADomina cada sonido
VocabularioConstruye tu banco de palabras
Juego de vocabularioAprende mientras juegas
Mismo canal
C11
Diodes Explained - The basics how diodes work working principle pn junction
Daily ConversationUniversity StudentsWorking Adults
B21
Air Conditioning System Basics hvacr how does it work
Daily ConversationWorking Adults
B22
How ELECTRICITY works - working principle
Daily ConversationUniversity StudentsWorking Adults
C1Centrifugal Pump Basics - How centrifugal pumps work working principle hvacr
Daily ConversationWorking Adults
FOR YOU
Recomendar Video
B21
29 oraciones
OHM's Law in 3 minutes (Beginner friendly)
Daily ConversationUniversity Students
B21
72 oraciones
Fight brain-rot with Worked Examples
Daily ConversationUniversity StudentsWorking Adults
B21
183 oraciones
Concept of Electric Current with Train example | TheElectricalGuy
Daily ConversationUniversity Students
B21
378 oraciones
Teaching Myself Electronics (Part One)
Daily ConversationUniversity Students
B2158 oraciones
7 Cấp Độ Toán Học: Bạn Đang Ở Đâu?
Daily ConversationUniversity Students
B21
162 oraciones
Introduction to PLC | Siemens PLC Training Course
Daily ConversationUniversity Students
C13
279 oraciones
LET THERE BE... Voltage? | Maxwell's Equation #2 Explained for Beginners
Daily ConversationUniversity Students
B21
425 oraciones
NEW- Micro Unit 1 Summary- Basic Economic Concepts
Daily ConversationHigh School StudentsUniversity Students
B22
38 oraciones
Internet of Things (IoT) Explained in 3 minutes
Daily ConversationUniversity StudentsWorking Adults
B13
9 oraciones
Walter Lewin explains Newton's third law
Daily ConversationHigh School StudentsUniversity Students
C11
166 oraciones
Introduction to Optoelectronics and Photonics
Daily ConversationUniversity Students
Vocabulario y notas de pronunciación para esta lección
Esta lección de conversación se basa en el vídeo “Ohms Law Explained - The basics circuit theory”. Las palabras que más se repiten: current, voltage, resistance, Amp, lamp. Este vídeo tiene 108 frases y 1796 palabras para practicar shadowing. La parte hablada dura 9:49. El hablante habla rápido, unas 183 palabras por minuto, así que espera sonidos enlazados y reducidos. Solo el 80 % de las palabras está entre las 3.000 más comunes del inglés, por lo que el vocabulario es exigente.
Vocabulario clave de este vídeo
15 palabras del vídeo que vale la pena aprender, con su pronunciación y significado:
| Palabra | Pronunciación | Significado |
|---|---|---|
| voltage sustantivo | /ˈvəʊltɪd͡ʒ/ | voltaje, tensión |
| lamp sustantivo | /ˈlæ̝mp/ | lámpara |
| divide verbo | /dɪˈvaɪd/ | desunir, dividir |
| triangle sustantivo | /ˈtɹaɪˌæŋɡəl/ | triángulo |
| connect verbo | /kəˈnɛkt/ | conectar, empalmar |
| litter sustantivo | /ˈlɪt.ɚ/ | cama, lecho |
| formula sustantivo | /ˈfɔː.mjʊ.lə/ | fórmula |
| metre sustantivo | /ˈmiːtəɹ/ | metro |
| atom sustantivo | /ˈætəm/ | átomo |
| wire sustantivo | /ˈwaɪɚ/ | alambre, hilo |
| solve verbo | /sɒlv/ | resolver, solucionar |
| experiment sustantivo | /ɪkˈspɛɹ.ə.mənt/ | experimento |
| copper sustantivo | /ˈkɒpə/ | cobre |
| relate verbo | /ɹɪˈleɪt/ | relatar |
| leaf sustantivo | /lif/ | hoja, foja (desus.) |
Phrasal verbs que vas a escuchar
| Palabra | Significado |
|---|---|
| cover up verbo | encubrir, cohonestar |
| write down verbo | apuntar, anotar |
| blow out verbo | apagar |
| check out verbo | investigar, chequear |
| come across verbo | pasarse a |
| light up verbo | iluminar |
Gramática en este vídeo
Las estructuras que más usa el hablante, con las palabras exactas del vídeo:
| Estructura | En el vídeo |
|---|---|
| Voz pasiva be + participio pasado — importa lo que ocurre, no quién lo hace | was developed · can be found · is named |
| Present perfect have/has + participio pasado — una acción pasada que sigue importando ahora | I've made · I've built |
| Oraciones de relativo who / which + oración — información extra sobre una persona o cosa | directions which is · lamp which has |
Pronunciación a tener en cuenta
El hablante usa 16 contracciones y formas reducidas, como don't, I'll, I've. Dilas en su forma corta, tal como las oyes.
- Los sonidos de “sh” y “zh”: shine /ʃaɪn/, shell /ʃɛl/, fraction /ˈfɹæk.ʃən/, calculation /ˌkælkjuˈleɪʃn̩/, multiplication /ˌmʌltɪplɪˈkeɪʃən/
- Palabras largas — cuida el acento: electrical /ɪˈlɛktɹɪkəl/, experiment /ɪkˈspɛɹ.ə.mənt/, naturally /ˈnæt͡ʃ.(ə.)ɹə.li/, intensity /ɪnˈtɛnsɪti/, visually /ˈvɪzju.əli/
Sonidos difíciles para hispanohablantes:
- /v/ — no es /b/: los dientes tocan el labio inferior: voltage /ˈvəʊltɪd͡ʒ/, divide /dɪˈvaɪd/, solve /sɒlv/, wherever /(h)wɛɹˈɛvɚ/, vary /ˈvɛəɹi/
- /z/ — sonora, no /s/: visually /ˈvɪzju.əli/, resistor /ɹɪˈzɪstɚ/, physicist /ˈfɪzɪsɪst/
Cómo practicar con este vídeo
- Escucha el vídeo entero una vez sin hablar y anota las palabras que no conoces.
- Empieza a velocidad 0,75×, haz shadowing frase por frase y vuelve a la velocidad normal cuando te resulte fácil.
- Grábate y compara con el original, prestando atención a palabras como voltage, lamp, divide.
¿Qué es la Técnica de Shadowing?
Shadowing es una técnica de aprendizaje de idiomas respaldada por la ciencia, desarrollada originalmente para la formación de intérpretes profesionales y popularizada por el políglota Dr. Alexander Arguelles. El método es simple pero poderoso: escuchas audio en inglés nativo y lo repites en voz alta de inmediato, como una sombra que sigue al hablante con solo 1-2 segundos de retraso. A diferencia de la escucha pasiva o los ejercicios de gramática, el shadowing obliga a tu cerebro y músculos de la boca a procesar y reproducir simultáneamente patrones de habla reales. Las investigaciones muestran que mejora significativamente la precisión de la pronunciación, la entonación, el ritmo, el habla conectada, la comprensión auditiva y la fluidez al hablar, convirtiéndola en una de las metodologías más efectivas para la preparación del IELTS Speaking y la comunicación en inglés en el mundo real.