B2 中高級 美國腔 43 分類 收藏
(electric guitar music)
- One of the coolest things I've discovered
about circuits is, circuitry can be an art form.
If I have a creative idea,
I can get that creative idea out using circuits.
So, if you have ideas, you can use technology to make
those ideas come to life.
Every input or output of a computer is effectively
a type of information, which can be represented
by on or off electrical signals.
Or one's and zero's.
In order to process the information that comes in,
as input, and the make the information that's output.
A computer needs to modify and combine the input signals.
To do this, a computer uses millions of tiny electronic
components, which come together to form circuits.
(upbeat music)
- Let's take a closer look at how circuits can modify
and process information that's represented
in one's and zero's.
This is an incredibly simple circuit.
It takes an electrical signal, on or off, and it flips it.
So, if the signal you give it is a one,
the circuit gives it a zero.
And if you give the circuit a zero, it gives you a one.
The signal that goes in, is not the same as the signal
that comes out.
And so, we call the circuit, not.
- More complicated circuits can take multiple signals
and combine them, and give you a different result.
In this example, a circuit will take two electrical signals.
Now, each one might be a one or a zero.
If either of the signals coming in is a zero,
then the result is also a zero.
This circuit will only give you a one
if the first signal and the second signal are both a one.
And so, we call this circuit, and.
There are many small circuits like this,
that perform simple, logical calculations.
But connecting these circuits together,
we can make more complex circuits
that perform more complex calculations.
For example, you can make a circuit that adds two bits
together called, an adder.
This circuit takes in two individual bits, each one, a one
or a zero, and adds them together to calculate the sum.
The sum can be zero plus zero equals zero,
zero plus one equals one, or one plus one equals two.
You need two wires coming out because it can take up to two
binary digits to represent the sum.
Once you have a single adder for adding two bits of
information, you can put together multiples of these adder
circuits side by side to add together much larger numbers.
- For example, here's how an eight bit
adder adds the numbers 25 and 50.
Each number is represented using eight bits
resulting in 16 different electrical signals
that go into the circuit.
The circuit for an eight bit adder has lots of little adders
inside of it, which together, calculate the sum.
Different electrical circuits can perform other simple
calculations like subtraction or multiplication.
In fact, all the information processing your computer does
it's just lots and lots
of small simple operations put together.
Each individual operation done by a computer
is so, so simple, it could be done by a human.
But these circuits inside computers are way, way faster.
- Back in the day, these circuits were big and clunky.
An an eight bit adder could be as big as a fridge
and it would take minutes for them
to perform a simple calculation.
Today, computer circuits are microscopic in size
and way, way faster.
Why are smaller computers also faster?
- Well, because the smaller the circuit is,
the less distance the electrical signal has to go.
Electricity moves at just about the speed of light
which is why modern circuits can perform
billions of calculations per second.
- So, whether you're playing a game, recording a video,
or exploring the cosmos, everything you can possibly do with
technology requires lots of information
to be processed extremely quickly.
Underneath all this complexity,
is just lots of teeny little circuits that turn binary
signals into websites and videos, music and games.
These circuits can even help us
decode DNA to diagnose and cure disease.
(upbeat music)


可汗學院和Code.org | 電路與邏輯

43 分類 收藏
Henry 楊 發佈於 2020 年 6 月 8 日
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