16.2 当前
章节大纲
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You've probably heard of vacuum tubes and large transistors, which were once common in electronics like televisions. These individual devices were mounted on large printed boards. Then, in 1959, two researchers working independently developed the first integrated . These circuits could combine several transistors and resistors into one circuit on one small chip of silicon. These chips, like the one pictured above, are used today in virtually every electrical device.
::你可能听说过真空管和大型晶体管,这些曾经在像电视这样的电子设备中很常见。这些个别装置安装在大型印刷板上。然后,1959年,两名独立工作的研究人员开发了第一个集成集成装置。这些电路可以将几个晶体管和阻力器合并成一个小硅芯片的电路。这些芯片和上面所描述的芯片一样,今天几乎在每个电子装置中都使用。Electric Current and Circuits
::电流电路和电路Electric Current
::电电流电流Remember that it often requires work to force electrons into a specific location. If we have two conducting spheres and we have forced excess electrons onto one of the spheres by doing work on the electrons, then that sphere, and those electrons, will have a higher than those on the uncharged sphere. If the two spheres are touched together, electrons will flow from the sphere with excess electrons to the sphere with no excess electrons. That is, electrons will flow from the high potential energy position to the lower potential energy position. The flow will continue until the electrons on the two spheres have the same potential energy. A flow of charged particles such as this is called an electric current .
::记住它常常需要工作才能将电子强制到特定的位置。 如果我们有两个操作场,我们通过在电子上做工作迫使超电子进入其中的一个区域, 那么这个球和那些电子将比在未充电的球体上高一些。 如果这两个球体被连接在一起, 电子将带着超电子从球体流到没有超电子的球体上。 这就是说, 电子将从高潜在能量位置流到低潜在能量位置。 流将一直持续到两个球体上的电子具有同样的潜在能量。 像这样的充电粒子流被称为电流。It is possible for an electric current to be either a flow of positively charged particles or negatively charged particles. In gases, both positive and negative ions can flow. The difficulty of freeing protons , however, makes it extremely rare to have an electric current of positive particles in solid conductors. Virtually all electric currents consist of the movement of electrons.
::电流既可以是正电荷粒子流动,也可以是负电荷粒子流动。在气体中,正离子和负离子都可以流动。然而,释放质子的困难使得在固体导体中产生正电流的正粒子极为罕见。几乎所有电流都包含电子移动。Common Misconceptions
::常见误解It is easy to assume that current is the flow of positive charges. In fact, when the conventions of positive and negative charge were invented two centuries ago, it was assumed that positive charge flowed through a wire. In reality, however, we know now that the flow of positive charge is actually a flow of negative charge in the opposite direction. That is, when an electron moves from position A to position B, it is the same as a positive hole moving from B to A.
::事实上,当两个世纪前发明了正面和负面指控的公约时,人们就以为正电荷通过电线流通。 然而,事实上,我们现在知道正电量的流通实际上是相反方向的负电荷流动。 也就是说,当电子从A位置移到B位置时,它与从B位置移到A位置的正空洞是一样的。Today, even though we know it is not correct, we still use the historical convention of positive current flow when discussing the direction of a current. Conventional current , the current we commonly use and discuss, is the direction positive current would flow. When we want to speak of the direction of electron flow, we will specifically state that we are referring to electron flow.
::今天,尽管我们知道这是错误的,但我们仍然在讨论潮流的方向时使用正流的历史惯例。 我们通常使用和讨论的当前是正流的方向。 当我们想谈论电子流的方向时,我们将明确指出我们指的是电子流。Electric current flows from positions of higher potential energy to positions of lower potential energy. Electrons acquire higher potential energy from an electron pump that does work on the electrons, moving them from positions of lower PE to positions of higher PE . Electrons in galvanic cells (several cells together comprise a battery) have higher potential energy at one terminal of the battery that at the other. This difference in potential is related to chemical . When the two terminals of the battery are connected to each other via a conducting wire, the electric current will travel from the terminal with higher potential energy to that with lower potential energy. This setup is the most simple of electric circuits .
::电流从高潜在能量的位置流到低潜在能量的位置。 电能从电子泵中获取更高的潜在能量,电子泵对电子起作用,将电子泵从低PE的位置移到高PE的位置。 电极电池中的电子(多个电池合在一起组成一个电池)在电池的一个终端中具有更高的潜在能量,而另一个电池的终端中具有更高的潜在能量。这种潜力差异与化学有关。当电池的两个终端通过导电线连接时,电流将从具有较高潜在能量的终端通到具有较低潜能的终端。这种装置是最简单的电路。It can be helpful to think about an electric circuit like water flowing through a system. Use the Electric Analogies simulation below to help you visualize what is going on in an electric circuit. The pump and water tower represent the battery and the water wheel represents a resistor. You can adjust the slider to put these “resistors” in series and in parallel. Have fun exploring:
::思考像水流通过一个系统那样的电路可能会有帮助。 使用下面的电解模拟来帮助您想象电路中发生的情况。 泵塔和水塔代表电池, 水轮代表抵抗器。 您可以调整滑动器, 将这些“ 阻力器” 放在序列和平行中 。 玩得开心地探索 :Electric Circuits
::电电电线路An electric circuit is any closed loop that goes from one battery terminal to the other and allows current to flow through it. A relatively simple circuit is shown in the image below. The charges move from the higher potential energy terminal on the battery, through the light bulb, through the switch, and back to the lower potential energy terminal on the battery.
::电路是指从一个电池终端通向另一个电池终端并允许电流通过电路的任何闭路循环。下面的图像显示的是相对简单的电路。电路从电池上更高的潜在能源终端,通过灯泡,通过开关,再回到电池上较低的潜在能源终端。Other resistors include motors, which convert energy into , and heaters, which convert it into . A circuit consists of a battery, or a charge pump, which increases the potential energy of the charges, and one or more devices that decrease the potential energy. As the potential energy is reduced, it is converted into some other form of energy. In the image above, the device that decreases the charges' potential energy is the light bulb; the excess energy is converted into light energy. Any device that reduces the potential energy of the charge flowing through it is said to have because it resists the flow of charge.
::其他抗体包括能转换成能量的发动机和能转换成能量的加热器。电路由电池或充电泵组成,增加电荷的潜在能量,以及一种或多种减少潜在能量的装置组成。随着潜在能量的减少,它被转化成某种其他形式的能量。在以上图像中,降低电荷潜在能量的装置是灯泡;多余能量被转换成光能。据说,任何能减少电荷潜在能量的装置,因为其阻力会阻力电流。The charges in the circuit can neither be created nor destroyed, nor can they pile up in one spot. The charged particles moving through the circuit move the same everywhere in the circuit. If one coulomb of charge leaves the charge pump, then one coulomb of charge moves through the light, and one coulomb of charge moves through the switch. The net change of energy through the circuit is zero. That is, the increase in potential energy through the charge pump is exactly equal to the potential drop through the light. If the (charge pump) does 120 J of work on each coulomb of charge that it transfers, then the light uses 120 J of energy as the charge passes through the light.
::电路中的电荷既不能产生,也不能销毁,也不能堆积在一个点上。通过电路的充电粒子在电路中随处移动。如果一个充电柱离开充电泵,那么一个充电柱穿过光线,一个充电柱穿过开关。电路的能量净变化为零。也就是说,通过充电泵的潜在能量增加与通过光线的潜在下降量完全相等。如果(充电泵)对传输的电荷每个波柱进行120焦耳的工作,那么电荷通过光线时使用120焦耳的能量。The electric current is measured in coulombs per second. A flow of one coulomb per second is called one ampere , A, of current.
::电流以每秒Coulombs测量。每秒一个comulomb 的流量被称为 an ampere, A 。@$$\begin{align*}1.00 \ \text{Ampere}=\frac{1.00 \ \text{coulomb}}{1.00 \ \text{second}}\end{align*}@$$
::@ $\ begin{ ALIGN} @ 1. 00\\\ text{ ampere}\ frac{ 1. 00\\\ text{ coulomb}\ 1. 00\\\ text{ second{ end{ align} $The energy carried by an electric current depends on the charge transferred and the potential difference across which it moves, @$\begin{align*}E = qV\end{align*}@$ . The or potential difference is expressed in Joules/coulomb and multiplying this by the charge in coulombs yields energy in Joules .
::电流携带的能量取决于电流转移的电量及其移动中的潜在差异, @$\ begin{ align}_E = qV\ end{ align}_$。 或潜在差异以Joules/ coulomb 表示, 乘以 comulombs 中的电量, 在Joules 中产生能量 。Electrical power is a measure of the rate at which energy is transferred, and is expressed in watts, or Joules/second. Power can also be obtained by multiplying the voltage by the current:
::电力是衡量能源传输速度的一种尺度,以瓦特或朱列斯/秒表示。也可以通过电压乘以电流获得电力:Power, @$\begin{align*}P = VI = \left(\frac{\text{Joules}}{\text{coulomb}}\right)\left(\frac{\text{coulomb}}{\text{second}}\right) = \frac{\text{Joules}}{\text{second}} = \text{watts}.\end{align*}@$
::功率, @ $\ begin{ align} p = VI = left (\ frac\ text{ Joules} text{ coulomb}right)\ left (\ frac\ text{ coulomb} text{ second_ right) =\ frac\ text{ Joules} text{ second{ =\ text{watts}.\ end{ align} =$).\ end{ end{align} =\ frac\ text{ text{ secon_ text} =\ text{ text{ watts} =\ end{ end{align} =\ leight} left(\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\Examples
::实例Example 1
::例1What is the power delivered to a light bulb when the circuit has a voltage drop of 120 V and produces a current of 3.0 ampere?
::当电路的电压下降120伏,产生3.0安培电流时,灯泡的电能是什么?@$\begin{align*}P = VI = (120 \ \text{J/C})(3.0 \ \text{C/s}) = 360 \ \text{J/s} = 360 \ \text{watts}\end{align*}@$
::@ $\ begin{ align}\ p = VI = (120\ text{ J/ C} (3. 0\\\ text{ C/ s}) = 360\ text{ J/ s} = 360\ text{ watts} end{ align$ = 360\ text{watts} end{ end{align$ \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\ </span> </p> <button class="play-button btn btn-success" style="float: right;" value="@s"> 播放段落 </button> <h4 id="x-ck12-ZDdlMmFiYTQ4ODgxMGQ5OGIzNDRkNzVkZDU3NGNjYmE.-fgu"> <strong> Example <span> 2 </span> </strong> <br/> <span style="color: green; "> ::例2 </span> </h4> <button class="play-button btn btn-success" style="float: right;" value="@s"> 播放段落 </button> <p id="x-ck12-MjU2MTJkMTI4ZGI0NTkwMGExNTg0ZGJmZjI1MTRiN2I.-d9j"> A 6.00 V battery delivers a 0.400 A current to an that is connected across the battery terminals. <br/> <span style="color: green; "> ::A 6.00 V 电池能提供0.400 A 电流,通过电池终端连接到一个电流。 </span> </p> <ol class="x-ck12-lower-alpha" id="x-ck12-ODc0ZjA5NDMwMWI2YjhiYTc3MTRjZDc2MWRlMzA1NTk.-fpt" style="list-style-type: lower-alpha;"> <button class="play-button btn btn-success" style="float: right;" value="@s"> 播放段落 </button> <li> What power is consumed by the motor? <br/> <span style="color: green; "> ::发动机消耗的动力是什么? </span> </li> <button class="play-button btn btn-success" style="float: right;" value="@s"> 播放段落 </button> <li> How much electric energy is delivered in 500. seconds? <br/> <span style="color: green; "> ::500秒内能提供多少电能? </span> </li> </ol> <p id="x-ck12-NDliMjFhZDBkMzg5NDJmNjM1ODc3ZTdiYmM1ZDdhMWU.-tlj"> </p> <ol class="x-ck12-lower-alpha" id="x-ck12-9qk" style="list-style-type: lower-alpha;"> <button class="play-button btn btn-success" style="float: right;" value="@s"> 播放段落 </button> <li> <span class="x-ck12-mathEditor" data-contenteditable="false" data-edithtml="" data-math-class="x-ck12-math" data-mathmethod="inline" data-tex="P%20%3D%20VI%20%3D%20(6.00%20%5C%20%5Ctext%7BV%7D)(0.400%20%5C%20%5Ctext%7BA%7D)%20%3D%202.4%20%5C%20%5Ctext%7Bwatts%7D"> @$\begin{align*}P = VI = (6.00 \ \text{V})(0.400 \ \text{A}) = 2.4 \ \text{watts}\end{align*}@$
::@ $\ begin{ align}\ p = VI = (6. 00\\ text{ V} (0. 400\\\ text{ A}) = 2. 4\\ text{ watts} end{ end{ align$} = 2. \ text{watts} end{ end} = VI = (6. 00\\ text{V} (0. 400\\\\\ text{A}) = 2. \ text{watts} end{align$}- @$\begin{align*}\text{Joules} = (\text{J/s})(\text{s}) = (2.4 \ \text{J/s})(500. \ \text{s}) = 1200 \ \text{Joules}\end{align*}@$
::@ $\ begin{ align{ text{ Joules} = (\ text{ J/ s} (\ text{ {s}) = (2.4\\ text{ J/ s} (500.\\ text{s}) = 1200\\ text{ Joules} end{ end{ align} = (2.4\\ text{ J/ s} (500.\\ text{s} \\\ text{s} = 1200\\\\ text{ {Joules{end{ end{align} =1200\\\Launch the Flashlight simulation below to see how electricity flows in a simple circuit. Be sure to observe the Power vs Current graph to develop a deeper understanding of the relationship between these two variables. Can you adjust the sliders to maximize the current running through the circuit? Try it out:
::启动下面的闪光模拟, 以查看电流如何在简单电路中运行 。 请务必观察 Power 和 Rent 图形, 以加深对这两个变量之间关系的理解 。 您能否调整滑动器以尽量扩大电路运行中的电流 ? 试一下 :Further Reading
::继续阅读-
and Current
::和当前 -
Direct and
Alternating Current
::直接的和交替的当前
Summary
::摘要-
Electric current is the flow of electrons from the high potential energy position to the lower potential energy position.
::电流是电子从高潜在能源位置流向低潜在能源位置。 -
Current flow is the direction a positive current would be traveling, or the opposite direction that electrons actually flow.
::当前流是正流的方向,正流是流动的方向, 或电子实际流动的相反方向。 -
A closed loop containing current flow is called an electric circuit.
::包含当前流动的闭路环称为电路。 -
Electric current is measured in coulombs per second, or amperes.
::电流以每秒或安培量计。 -
Electric
power
is measured in joules per second, or watts.
::电能以焦耳/秒或瓦特测量。 -
The energy carried by an electric current depends on the charge transferred and the potential difference across which it moves,
@$\begin{align*}E = qV\end{align*}@$
.
::电流所携带的能量取决于电流转移的电量及其移动中的潜在差异, @$\ begin{align}E = qV\end{align}$。 -
Power,
@$\begin{align*}P = VI = \left(\frac{\text{Joules}}{\text{coulomb}}\right)\left(\frac{\text{coulomb}}{\text{second}}\right) = \frac{\text{Joules}}{\text{second}} = \text{watts}.\end{align*}@$
::功率, @ $\ begin{ align} p = VI = left (\ frac\ text{ Joules} text{ coulomb}right)\ left (\ frac\ text{ coulomb} text{ second_ right) =\ frac\ text{ Joules} text{ second{ =\ text{watts}.\ end{ align} =$).\ end{ end{align} =\ frac\ text{ text{ secon_ text} =\ text{ text{ watts} =\ end{ end{align} =\ leight} left(\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\
Review
::回顾-
The current through a light bulb connected across the terminals of a 120 V outlet is 0.50 A. At what rate does the bulb convert electric energy to light?
::电流通过一个灯泡,通过一个120伏特的终端连接到一个120伏特的终端是0.50A。灯泡将电能转换成光速的速率是多少? -
A 12.0 V battery causes a current of 2.0 A to flow through a lamp. What is the power used by the lamp?
::A 12. 0 V 电池使2.0 A 的电流通过灯泡流动。灯的电能是什么? -
What current flows through a 100. W light bulb connected to a 120. V outlet?
::电流是多少? 100个W光灯灯泡连接到120个V插座? -
The current through a motor is 210 A. If a battery keeps a 12.0 V potential difference across the motor, what electric energy is delivered to the motor in 10.0 s?
::电流通过马达是210A。如果电池在马达之间保持12.0V的潜在差异,10秒内向马达输送的电能是多少?
Explore More
::探索更多Use this resource to answer the questions that follow.
::使用此资源回答下面的问题 。-
What type of current is described in this video (electron or conventional)?
::本视频(电子或常规)描述的电流类型是什么? -
What drives the current through the circuit?
::是什么驱动电流通过电路? -
What inhibits the flow of current in the circuit?
::是什么抑制了电路中的流流?
- @$\begin{align*}\text{Joules} = (\text{J/s})(\text{s}) = (2.4 \ \text{J/s})(500. \ \text{s}) = 1200 \ \text{Joules}\end{align*}@$
