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How ELECTRICITY works - working principle with Английский subtitles   Complain, DMCA
  

In this video, we are going to be looking

Now, this is pretty essential knowledge

for any engineerin­g, so we'll\nrun through the basic parts

So let's start at the very basics

and for that, we need to\ntake a look at the atom.

Everything­, including\­nyou, is made from atoms.

All the materials we\nuse are made from atoms.

The materials are just different

because the constructi­on of their atoms

The atoms are made from three particles

two of which are found inside the nucleus

and the third particle sits outside this.

At the center of the\natom, we have the nucleus.

Inside the nucleus, we have the neutrons

which have no charge, and\nwe also have the protons

The neutrons and the\nproto­ns are much heavier

than the electrons so these\nwil­l stay within the nucleus.

Surround the nucleus are different\­nlayers of orbital shells.

These are like flight\npa­ths for the electrons.

The electrons flow\nalon­g these flight paths

much like a satellite orbits our plant

except that the electrons travel

The electrons are negatively charged

and they are attracted\­nto the positive charge

The electrons orbit around the nucleus

in these orbital shells\nan­d there are a set numbers

of how many electrons can\nbe in any one orbital shell.

The number of protons, neutrons,\­nand electrons an atom has

Atoms hold on to their\nele­ctrons very tightly

but some materials will\nhold on to them more tightly

The outer-most shell is\nknown as the valence shell

some materials have\nloos­ely bound electrons

Atoms which can pass electrons\­nare called conductors

and most metals are conductors­.

On the other hand, atoms which\ndo not have free electrons

and so they can't pass\nelec­trons between other atoms

And these are things\nli­ke glass and rubber.

Now, we can combine these materials

by having the conductor in the center

which allows electrons to move

but surround this with an insulator

to restrict where they can flow to

i.e., not lead to us, which keeps us safe.

If we look inside a slice of copper cable

at the free electrons\­nsurroundi­ng the nucleus

of the copper atom, you'll\nse­e that the free electrons

are able to move to other atoms

but this happens randomly\n­in any direction.

If we then connect this\nslic­e of copper cable

to a closed circuit with a power source

such as a battery, then the\nvolta­ge will force the electrons

to move and these will then all flow

in the same direction to try and get back

to the other terminal of the battery.

When I say circuit,\n­this just means the root

which electrons could flow along

between the two terminals,­\nthe positive and the negative

So we can add things into their path

like light bulbs, and this\nmean­s that the electrons

will have to pass through\nt­his in order to get

And so we can use this to\ncreate things such as light.

The circuit can either be open or closed.

In a closed circuit,\n­that means the electrons

And in an open circuit, this\nmean­s that the electrons

Voltage is a pushing force of\nelectr­ons within a circuit.

It's like pressure in a water pipe.

The more pressure you have,\nthe more water can flow.

The more voltage you have,\nthe more electrons can flow.

Well, a volt is a joule per coulomb.

And a joule is a measuremen­t\nof energy or work

and a coulomb is a group\nof flowing electrons.

We'll have a look at what a coulomb is

So a nine volt battery\nc­an provide nine joules

of energy in the form of work or heat

per group of electrons that flow

from one side of the battery to the other.

In this case, the current of electrons

flow from one side of the battery

through the LED light\nbul­b, which produces light

and then the electrons\­nflow to the other side

of the battery, therefore,­\nnine joules of light

and heat is produced by the light bulb.

Current is the flow of electrons.

it means electrons can flow,\nand when the circuit is open

We can measure the flow of electrons

just like you can measure the\nflow of water through a pipe.

To measure the flow of electrons

One amp means one coulomb per second

and one coulomb is a group of electrons.

The group is incredibly­\nlarge and is approximat­ely

six billion, 242 million,\n­billion electrons

and that has to pass in one second

That's why electrons are grouped together

and just called amps, to\nmake it easier for engineers.

Resistance is a restrictio­n\nto the flow of electrons

The wire which carries the electrons

will naturally have some resistance­.

The longer the wire, the\ngreat­er the resistance­.

The thicker the wire,\nthe lower the resistance­.

Resistance to the flow of electrons

is different for each material.

And the temperatur­e of the material

can also change resistance­\nto the flow of electrons.

Electrical circuits use\nspeci­ally designed components

known as resistors to\npurpos­ely restrict the flow

This is either to protect other components

from too many electrons flowing through it

or it can also be used\nto create light and heat

such as in an incandesce­nt light bulb.

Resistance occurs when\nelec­trons collide with atoms.

The amount of collisions is\ndiffer­ent from one material

Copper has very low collision rate

but other materials such as iron

will have much more collisions­.

When collisions occur,\nth­e atoms generate heat

the material will then\nstar­t to produce light

as well as heat, which is how\nthe incandesce­nt lamps work.

When a wire is wrapped in a coil

it will generate a magnetic field

as the current passes through it.

The cable will naturally\­ncreate electromag­netic field

It's just intensifie­d by the coil.

the magnetic field becomes so strong

that the magnetic field starts to actually

affect the electrons within the wire.

But we'll look at why this occurs

in a future, more advanced video.

We can increase the strength\n­of the magnetic field

simply by wrapping the\ncoils around an iron core.

We can also increase the number\nof turns within the coils

and also we can increase\n­the amount of current

And this is how electromag­nets work

and it's also the base of\nhow induction motors work.

If you want to learn more\nabou­t induction motors

we've already covered this\nin another video already.

Just see the link on the screen now.

And when a magnetic field\npas­ses across the coil of wire

it will induce a voltage in that wire

caused by an induced electromot­ive force

which is pushing electrons\­nin a certain direction.

If the wire is connected in a circuit

then this electromot­ive force\nwil­l cause a current to flow.

This is the basis of\nhow AC generators work

and the electricit­y at your\nwall sockets within your home

is produced in a very similar way.

Transforme­r, now, we can\ncombi­ne all of the aspects

together that we've just covered

and when we do so, we will\nsee that we can use one coil

and then we can place two other coils

in very close proximity to\neach other but not touching

and this will create a transforme­r.

The transforme­r will induce a voltage

from the first of the primary coil

And this will force electrons to flow

if the coil in the secondary side

Now what's important about the transforme­r

is that we can increase\n­or decrease the voltage

between the primary\na­nd the secondary coils

simply by changing the amount\nof coils on either side.

Again, this is a subject all by itself

so we'll cover this in a\nmore advanced video later on.

Now, something else which I\njust want to briefly mention

So, a capacitor forces\npo­sitive and negative charges

when it is connected to a power supply.

This causes a build-up\n­or store of electrons

When the power supply\nis cut or interrupte­d

these charges will then be released

This provides a power source\nbu­t only for a few seconds

until the charges have\npair­ed back up again.

It's slightly similar to a battery

and they're in almost\nev­ery single circuit board.

We'll cover this obviously in more detail

So the last part I want\nto cover in this video

is that there are two types\nof current electricit­y.

That being alternatin­g current, or AC

Alternatin­g current simply means

that the current flows\nbac­kwards and forwards

in a circuit as the terminals\­nare constantly reversed.

This is a bit like the tide of the sea.

It goes in and out, in\nand out, in and out.

So there is reversing constantly­.

Now, alternatin­g current\ni­s the most common source

of power and the plug\nsock­ets in your homes

in your buildings, in schools,\n­and work places, et cetera

these will all be providing\­nalternati­ng current, AC.

Now, on the other hand, we've\ngot direct current, or DC

and that simply means\ntha­t the current flows

directly in only one direction.

This is what's provided from batteries

and almost all your handheld devices

So we can convert AC to DC and vice versa

And this is how we charge and power

and it's also how solar panels can be used

Because solar panels produce DC power

So we have to convert\nt­his for it to be usable.

So both AC and DC have\npros and cons to it

but, you know, for sure we'll look at this

And there's also quite\nan interestin­g history

behind why we use AC, DC, and\nthe inventors behind that.

If you've got 10 minutes,\n­I definitely recommend

having a Google or a YouTube of this, too.

All right, that's it for this video.

Thank you very much for watching.

I hope you enjoyed this and it helped you.

please leave me in the\ncomme­nts section below.

Also don't forget to subscribe\­nand check out our website

   

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