We have an inductor, a transistor, a diode, and a capacitor.

我們有一個電感器，一個晶體管，一個二極管和一個電容器。

We also have a device to which we have to deliver power,

我們還有一個必須向其供電的設備，

represented here by a light bulb.

這裡用燈泡表示。

The connection to the gate of the transistor is not shown,

未顯示到晶體管柵極的連接，

but this is a voltage that we control.

但這是我們控制的電壓

Suppose we control this gate voltage in a way such that

假設我們以某種方式控制該柵極電壓

the transistor behaves like a switch, which we can turn on or off.

晶體管的行為就像一個開關，我們可以打開或關閉它。

If we close the switch, we will cause a DC voltage to appear across the inductor.

如果關閉開關，將導致直流電壓出現在電感兩端。

The current through the inductor will keep increasing,

通過電感的電流將持續增加，

so long as the switch is closed.

只要開關閉合即可。

The current through an inductor can not change instantaneously.

流過電感的電流不能瞬時改變。

Therefore the moment we open the switch,

因此，當我們打開開關的那一刻，

the inductor will create a force causing the current to continue flowing.

感應器將產生一個力，使電流繼續流動。

Suppose we keep turning the switch on and off.

假設我們一直打開和關閉開關。

By continuously turning the switch on and off,

通過持續打開和關閉開關，

we have created a DC output voltage at the light bulb

我們在燈泡上創建了直流輸出電壓

that is higher than the voltage of the battery.

高於電池電壓。

We call this a “Boost Converter.”

我們稱其為“升壓轉換器”。

We can control the value of the DC output voltage at the light bulb

我們可以控制燈泡的直流輸出電壓值

by controlling the percentage of time that this switch is on.

通過控制此開關打開的時間百分比。

Suppose that we leave the switch off all the time.

假設我們一直關閉開關。

With the switch off 100% of the time,

在100％的時間關閉電源的情況下，

the output voltage will equal the voltage of the battery.

輸出電壓將等於電池的電壓。

What if we instead have the switch on most of the time?

如果我們大多數時候都打開電源怎麼辦？

If the switch is almost always on,

如果開關幾乎總是打開，

then assuming we have ideal components,

然後假設我們有理想的組件，

the current will theoretically keep increasing to infinity.

從理論上講，電流將繼續增加到無窮大。

During the brief moment when we turn the switch off,

在短暫的時間內，當我們關閉開關時，

an infinite current would charge the capacitor to an infinite voltage.

無限大的電流會將電容器充電至無限大的電壓。

By selecting the appropriate percentage of time that the switch is on,

通過選擇開關打開的適當時間百分比，

we can set the output voltage to any value that is larger than the battery voltage.

我們可以將輸出電壓設置為大於電池電壓的任何值。

But, we will need a different circuit to produce a

但是，我們將需要不同的電路來產生

steady state output voltage that is smaller than the battery voltage.

穩態輸出電壓小於電池電壓。

At first, this may seem simple,

首先，這似乎很簡單，

as this can be done by using resistors to create a voltage divider.

因為這可以通過使用電阻器創建分壓器來完成。

But, the problem is that we want to be efficient,

但是，問題是我們要提高效率，

and resistors dissipate energy as heat.

電阻將能量耗散為熱量。

Any energy that is lost as heat in a resistor

電阻中作為熱量損失的任何能量

is not delivered to the device which we wish to power.

沒有交付給我們希望供電的設備。

If we don't care about efficiency,

如果我們不在乎效率，

but just want to be able to adjust the output voltage,

但只想能夠調整輸出電壓，

we can do it through a circuit such as this one.

我們可以通過這樣的電路來做到這一點。

The energy lost as heat in the transistor is the voltage across the transistor,

由於晶體管中的熱量而損失的能量是晶體管兩端的電壓，

multiplied by the current passing through it.

乘以通過它的電流。

Now, consider the following.

現在，考慮以下內容。

If we operate and think of the transistor as an ideal switch,

如果我們操作並認為晶體管是理想的開關，

then when the switch is off, the current is zero…

然後，當開關斷開時，電流為零…

And when the switch is on, the voltage across it is zero.

當開關接通時，其兩端的電壓為零。

Therefore, in theory, if the transistor is either fully “on” or fully “off”,

因此，理論上，如果晶體管完全“導通”或完全“截止”，

and never somewhere in between, the voltage multiplied by the current is always zero,

而且介於兩者之間的任何地方，電壓乘以電流始終為零，

and there is no energy dissipated as heat in the transistor.

而且晶體管中沒有能量作為熱量散發。

But, if we want to be 100% efficient, we also have to get rid of the resistor.

但是，如果我們想提高效率100％，則還必須去除電阻器。

Suppose that in this circuit, we always operate the transistor as an ideal switch.

假設在此電路中，我們始終將晶體管用作理想開關。

If we keep opening and closing the switch,

如果我們繼續打開和關閉開關，

the “average” voltage across the light bulb

燈泡上的“平均”電壓

will be less than the voltage of the battery,

將小於電池的電壓，

but this is only because the voltage across the light bulb

但這僅僅是因為燈泡兩端的電壓

is zero when the switch is open.

開關斷開時為零。

We can try to prevent the voltage from dropping to zero

我們可以嘗試防止電壓降至零

by adding a capacitor across the light bulb.

通過在燈泡兩端增加一個電容器。

But now, when we close the switch,

但是現在，當我們關閉開關時，

we are trying to change the voltage of a capacitor instantaneously,

我們正在嘗試立即更改電容器的電壓，

which is impossible.

這是不可能的。

As a result, an extremely large current will flow to charge the capacitor,

結果，將流過非常大的電流來為電容器充電，

and this can cause considerable damage.

這會造成相當大的損害。

We can try to reduce this current by adding a resistor.

我們可以嘗試通過添加一個電阻來減小此電流。

But, as we said before, we do not want a resistor

但是，正如我們之前所說，我們不需要電阻

because resistors dissipate energy as heat.

因為電阻將能量耗散為熱量。

Instead of using a resistor, we can limit the current by using an inductor.

代替使用電阻器，我們可以通過使用電感器限制電流。

An ideal inductor does not dissipate energy as heat.

理想的電感器不會將能量耗散為熱量。

But, since the current through an inductor can't change instantaneously,

但是，由於流過電感的電流不能瞬時變化，

the inductor will force the current to keep flowing through the switch

電感器將迫使電流保持流過開關

even after we open it, which is an extremely dangerous phenomena.

即使我們打開它，這也是一個極其危險的現象。

We can prevent the current from flowing through the open switch by adding a diode.

我們可以通過增加一個二極管來防止電流流過斷開的開關。

The diode will give the current a different path to flow through.

二極管將為電流提供不同的流過路徑。

We call this circuit a “Buck converter.”

我們將此電路稱為“降壓轉換器”。

We can control the value of the DC output voltage at the light bulb

我們可以控制燈泡的直流輸出電壓值

by controlling the percentage of time that this switch is on.

通過控制此開關打開的時間百分比。

This allows us to create any DC voltage at the light bulb

這使我們可以在燈泡上產生任何直流電壓

that is lower than the voltage of the battery.

低於電池電壓。

Assuming that we had ideal components, this circuit would be 100% efficient.

假設我們有理想的組件，則該電路的效率為100％。

This is because ideal capacitors, ideal inductors, and ideal switches

這是因為理想的電容器，理想的電感器和理想的開關

do not dissipate any energy as heat.

不要耗散任何能量作為熱量。

We are thinking of the transistor as an ideal switch.

我們認為晶體管是理想的開關。

An ideal diode can also be thought of as a switch.

理想的二極管也可以認為是開關。

The diode is an “off switch” when it is blocking current

當二極管阻止電流時，它是一個“關斷開關”

from flowing in the reverse direction,

不會反向流動

and the diode is an “on switch” when current flows in the forward direction.

當電流正向流動時，二極管為“導通開關”。

The Buck converter uses the exact same components

Buck轉換器使用完全相同的組件

as the Boost converter, just arranged differently.

作為Boost轉換器，只是佈置不同。

In the real world, of course, these components are not ideal,

當然，在現實世界中，這些組件並不理想，

and they do in fact dissipate power.

實際上，它們確實在消耗功率。

Therefore, to maximize efficiency, actual power converts

因此，為了最大化效率，實際功率會轉換

are typically more complicated than the circuits shown here.

通常比這裡顯示的電路複雜。

But, the basic principles are the same.

但是，基本原理是相同的。

These basic principles are that transistors are operated as switches.

這些基本原理是將晶體管用作開關。

We never try to change the voltage across a capacitor instantaneously.

我們永遠不會嘗試立即改變電容器兩端的電壓。

And we never try to change the current through an inductor instantaneously.

而且，我們絕不會嘗試立即改變通過電感器的電流。

Much more information is available in the other videos on this channel,

該頻道的其他視頻提供了更多信息，

and please subscribe for notifications when new videos are ready.

當新視頻準備就緒時，請訂閱通知。