performing tasks unimaginable only decades ago.

執行僅數十年前 大家無法想像的工作

This was made possible by a long series of innovations,

這是藉由一系列的創新所致

but there's one foundational invention that almost everything else relies upon:

但幾乎其他東西 都依賴著一個基礎發明：

the transistor.

電晶體

So what is that,

那是什麼？

and how does such a device enable all the amazing things computers can do?

這個裝置是如何讓電腦 做所有神奇的事？

Well, at their core, all computers are just what the name implies,

實質上，所有的電腦（電子計算機） 都正如其名

machines that perform mathematical operations.

是執行數學運算的機器

The earliest computers were manual counting devices,

最早的計算機是手動的計算裝置

like the abacus,

像算盤

while later ones used mechanical parts.

之後的由機械零件所組成

What made them computers was having a way to represent numbers

能成為計算機 是因為它們有代表數字的方式

and a system for manipulating them.

且擁有可操作數字的系統

Electronic computers work the same way,

電子計算機（電腦） 也是用相同的原理

but instead of physical arrangements,

但不用實物來配置

the numbers are represented by electric voltages.

而是用電壓來代表數字

Most such computers use a type of math called Boolean logic

大部份的電腦用「布爾邏輯」數學運算

that has only two possible values,

它僅有兩種可能值

the logical conditions true and false,

即邏輯狀態的「真」與「假」

denoted by binary digits one and zero.

以二進位數的 1 和 0 來表示

They are represented by high and low voltages.

它們相當於高與低電壓

Equations are implemented via logic gate circuits

方程式是經由「邏輯閘」電路而形成

that produce an output of one or zero

產生了輸出值 1 或 0

based on whether the inputs satisfy a certain logical statement.

依據輸入端 是否吻合特定的邏輯語句而定

These circuits perform three fundamental logical operations,

這些電路執行三個基礎邏輯運算

conjunction, disjunction, and negation.

合取（及）、析取（或）、否定（非）

The way conjunction works is an "and gate" provides a high-voltage output

合取的運作方式是 及閘 (AND gate)

only if it receives two high-voltage inputs,

只在接收兩個高壓 (1) 輸入時 才會有高壓 (1) 輸出

and the other gates work by similar principles.

其他的閘也依循著相似的規則

Circuits can be combined to perform complex operations,

電路可被組合而執行複雜的運算

like addition and subtraction.

像加法和減法

And computer programs consist of instructions

而電腦程式 由透過電子進行運算的指令所組成

for electronically performing these operations.

這種系統需要 可靠且精準的方法以控制電流

This kind of system needs a reliable and accurate method

早期的電腦 如 電子數值積分計算機 (ENIAC)

for controlling electric current.

使用所謂「真空管」的裝置

Early electronic computers, like the ENIAC,

它早期型態為 二極管 (diode)

used a device called the vacuum tube.

由在真空玻璃容器裡的兩個電極所組成

Its early form, the diode,

施加電壓於陰極 會使其升溫並且釋放電子

consisted of two electrodes in an evacuated glass container.

如果陽極處於稍高的正電位狀態

Applying a voltage to the cathode makes it heat up and release electrons.

電子將會被其吸引

If the anode is at a slightly higher positive potential,

完成了整個電路

the electrons are attracted to it,

這種單向電流 可因施加不同電壓於陰極而被控制

completing the circuit.

使它放出更多或更少的電子

This unidirectional current flow could be controlled

下一個階段是 三極管 (triode)

by varying the voltage to the cathode,

使用了稱為「柵極」的第三個電極

which makes it release more or less electrons.

這是位於陰極和陽極間的鐵絲屏幕

The next stage was the triode,

電子可通過此屏幕

which uses a third electrode called the grid.

控制柵極的電壓可使其排斥 或吸引由陰極發射出的電子

This is a wire screen between the cathode and anode

如此可以快速轉換電流

through which electrons could pass.

三極管有放大信號的能力， 因而對收音機和遠距通訊極為重要

Varying its voltage makes it either repel

雖然有這些進展， 但真空管不穩定且龐大笨重

or attract the electrons emitted by the cathode,

配備 18,000 個三極管的 ENICA 幾乎是一個網球場大

thus, enabling fast current-switching.

且重達 30 噸

The ability to amplify signals also made the triode crucial for radio

三兩天就有幾個真空管破損

and long distance communication.

且在 1 小時內 就耗費 15 個家庭一天的用電量

But despite these advancements, vacuum tubes were unreliable and bulky.

解決方法為電晶體

With 18,000 triodes, ENIAC was nearly the size of a tennis court

它以半導體代替電極

and weighed 30 tons.

例如矽，以不同元素加以處理

Tubes failed every other day,

製造一個發射電子的 N 型 (negative type)

and in one hour, it consumed the amount of electricity used by 15 homes in a day.

及一個吸收電子的 P 型 (positive type)

The solution was the transistor.

它們被排列成三個交替層

Instead of electrodes, it uses a semiconductor,

每層各接一個電極

like silicon treated with different elements

發射極、基極、集電極

to create an electron-emitting N-type,

在這個典型的 NPN 電晶體裡

and an electron absorbing P-type.

因為 P-N 介面的特定現象

These are arranged in three alternating layers

位於發射極和基極間的特殊區域， 稱為 P-N 接面 (P-N junction)

with a terminal at each.

當施以超過一定閾值的電壓時， 它才能導電

The emitter, the base, and the collector.

否則，它會處於斷電狀態

In this typical NPN transistor,

這樣，輸入電壓中的微小變化 可用來快速轉換高與低輸出電流

due to certain phenomena at the P-N interface,

電晶體的優勢在於其效率和緊密度

a special region called a P-N junction forms between the emitter and base.

因為它們不須加熱， 所以更為耐用且省電

It only conducts electricity

ENIAC 的功能現在已被一個指甲大小 內含數十億電晶體的微晶元所超越

when a voltage exceeding a certain threshold is applied.

在每秒數兆的運算下

Otherwise, it remains switched off.

現代的電腦可能看起來像在表演魔術

In this way, small variations in the input voltage

但深藏在一切之下， 每個運算仍像按一下開關那麼簡單

can be used to quickly switch between high and low-output currents.

The advantage of the transistor lies in its efficiency and compactness.

Because they don't require heating, they're more durable and use less power.

ENIAC's functionality can now be surpassed by a single fingernail-sized microchip

containing billions of transistors.

At trillions of calculations per second,

today's computers may seem like they're performing miracles,

but underneath it all,

each individual operation is still as simple as the flick of a switch.