I am one of the co-founders of Arduino.

Welcome to this series of videos

about the Arduino Starter kit.

In this particular video,

we are going to start

learning the basics of all the

components that we are going to use

in the rest of the videos.

What we see here is

is a set of electronic components

and today we are going to

build a very basic circuit.

We are going to use a small LED

connected to a button

and when you press the button,

the LED comes on.

It's a very simple

electronic circuit.

It doesn't involve

our Arduino board at all.

And it is designed for you

to understand all the basic elements

that make

an electronic circuit.

So what is an LED?

An LED is a small source of light.

You can imagine it's

like a light bulb,

but it's more efficient,

because it doesn't generate that much heat.

Because it is an electronic component

based on the semi-conductor.

So LEDs are convenient for us,

because they work at

a small voltage.

They can be powered by a small battery

or the voltage that you

can get from an Arduino board.

So, what’s is a circuit?

A circuit is a series of electronic

components like

this LED

or this button using wires

connected together

Using wires

electricity can flow

through the components

and each component

is either able to transform

the electricity

into something else, like light

like the LED does.

Or for example

the switch

is a component that can

open and close a circuit

when you press on it.

This particular button

that I have in my hand

keeps the circuit closed

until I press the button,

and it closes the circuit.

Closing the circuit is a little bit like

when you open a tap:

you let the electricity

flow through the button.

You can imagine that Electricity

is like water

and the wires that we are using to make

the connection are like pipes.

The source of electricity

is essentially

the equivalent of something

that pushes water

into the pipes.

So the first circuit

that we are going to build

is going to

have the source of electricity

pushing the

current through the wires,

a number of wires

that connect to the button.

Then the button

will open and close the circuit

and when the circuit is closed,

the current will flow through the LED.

and then we will use another component

that I have here, called resistor.

What happens is that

the voltage of our battery

is too high

for the LED that we are using.

Just to give you an idea,

we are going to be

using a source of electricity

operating at 5 volts,

which is the standard voltage

at which the Arduino board operates.

But this LED

is only going to need about 1.7 volts.

So how do we make sure

the LED doesn't take

too much current?

Well, we are going to use a resistor.

And this resistor is going to limit

the amount of current

that flows through the LED,

keeping it at the optimum

amount of voltage and current.

How do we make the connection?

Well, actually

what happens with circuits is that

you can take wires,

and you can wrap them around,

and you can create circuits like that.

But that's not very practical.

If you want to do a lot of experimentation,

if you want to move

components around, if you want

to try different kinds of circuits,

wrapping wires around

is not exactly the best idea.

So what are we going to do?

We are going to use these

components that you see here.

This is called breadboard.

The breadboard

essentially provides a set of

prearranged connections,

and each one of the holes

is actually connected underneath

with a metallic spring.

So when I plug a wire

into the breadboard,

the spring will hold on to the wire

and it will connect to

all the other

holes in the same line of holes.

Let's have a look.

For example,

this line of holes

that I am pointing

to,

they are all connected together.

So if I plug this wire in this hole,

all the holes

in the same column

are going to be connected to this wire.

If I take for example this resistor,

and I plug the resistor

in one hole in the same line,

for example here.

This is ok.

So at the moment, the resistor

and the wire are connected together.

If I move this wire

to the hole next to it,

they are not connected anymore

because only the wires

in the same column

are connected together.

So, to explain this concept better,

I have prepared here

a circuit

that contains

all the basic elements that I

told you about.

This is the resistor,

this is the push button,

this is the LED,

and this is a wire.

So what's missing here

is the source of power.

What the circuit needs

in order to operate

is a source of electricity.

In this case

we are going to use

the Arduino board

as a source of electricity.

The Arduino board can be

powered through a battery

or through a USB connection

as you can see in this particular

situation. We are not going to use

the intelligence

provided by the Arduino board.

We are just going to use

the power

that comes

from the Arduino board

in order to learn

how to build the circuit

on the breadboard.

We are going to connect

this wire

to the other leg of the resistor.

You will notice that

actually the holes

on this side of the breadboard,

they have a different pattern.

Why is this?

Because actually

these two lines of

holes follow a different

connection pattern.

The ones

that cover the main area

of the breadboard

as I said, they are all connected

along the column,

while these

lines

are going

all the way

from one end

to the other.

These are two separate

strips

of holes,

and each one of them is connected

together. So, for example, if I plug

this red wire

at the beginning of this line of holes,

I am actually connecting

5 volts

to every single hole

that you can see

on this line here.

This means that this resistor

is now connected to this hole.

Now I am going to take this black wire

and I am going to plug it in

one of these two holes.

They are marked

GND

GND is the ground.

It also represents the

minus on your battery.

If you look at a battery

normally there's a plus and a minus.

So, 5V

represents the plus on this

ideal battery,

and the minus is

here represented by GND.

So, if i connected

the black wire

to the other line

on the breadboard,

now I have connected

5V to the first line of

holes

and the black wire

to the second line

of holes.

Now if everything is done correctly,

if I pressed the button,

I would connect the resistor

to the LED.

This will complete the circuit

and the LED

will light up.

wow.

Ok,

it's working.

Ok, that was good.

So the ability to convert

the electricity

into another physical phenomenon

that we can actually experience

in the real world

makes the LED a transducer.

The transducer is a component,

which is able to convert

electricity into something else.

or

for example

if there were a component

that would convert the light

back into electricity

that would also be a transducer.

In particular

we call the LED

in this particular situation

an actuator

because it takes electricity

and then turns into something that I

can actually see

in the real world. In this case,

I can see light.

Electricity is invisible to me,

but the LED makes

the electricity visible

by turning it into light.

We have our completed circuit

and I would like to make some

modifications now

to introduce some other concepts.

So what we are looking at here

is a very simple circuit,

where

each component is connected

to the next component

in the circuit,