Cell Phone Charger 手机充电器

In this lesson you will learn how to read an electrical schematic, and identify a variety of electrical components such as: diodes, resistors, capacitors, and many more. Finally, you will also learn how to build and test a prototype circuitboard. This will require you to analyze the electrical schematic that you have been given and then build the corresponding circuit. To do this successfully you will need to think about each component that you use, its polarity, and how each component connects to the other components in the circuit. When you are completed, you will have a circuit that looks similar to the example shown below.

在本课程中，你将学习如何读取电气原理图，并识别各种电气元件，如：二极管、电阻器、电容器等。此外，还将学习如何构建和测试原型电路板。分析所给的电气原理图，然后构建相应的电路。要成功地做到这一点，需要考虑使用的每个组件、极性以及每个组件如何连接到电路中的其他组件。成品如下图所示。

Video Tutorial 视频教程

There are 4 different levels of circuits available to try depending on your current skill level. It is recommended that you attempt the “Standard” design and then opt for either the “Basic” or “Advanced” options if you need something that is either more accessible or challenging.

有4种不同级别的电路可供尝试。建议先尝试“标准”设计，然后选择“基本”设计，如果想要有挑战性一点的可以选择“高级”设计。

Once you complete your circuit you will want to test it; however, it is recommended that you DO NOT plug your project into your brand new cellphone as you could damage your phone if your circuit is not perfect. Have your teacher test the circuit and use a test device or old cellphone that is no longer being used to see if your circuit works.

完成电路后进行测试；但是，建议不要直接新手机上测试，以防你的设计还不可行则有可能损坏手机。咨询老师使用一个测试设备或不再使用的旧手机来测试。

Extension Questions 拓展问题

When comparing the various cellphone charger models you may notice that some electrical components are used in each and every design, while other components are only used in the more complex designs.

在比较各种手机充电器型号时，你可能会注意到，每种设计中都使用了一些电气部件，而其他部件仅在更复杂的设计中使用。

1. What components are used in every USB cellphone charger design, and what do they do?
   每个USB手机充电器设计都使用哪些组件，它们的作用是什么？
2. What components are only used in some designs, and what do these components do?
   哪些组件仅在某些设计中使用，这些组件的作用是什么？
3. If the circuit can work without certain components why would you include them? provide at least one example to support your claim.
   如果电路可以在没有特定组件的情况下工作，为什么要包括它们？请至少提供一个示例来解释。
4. How dose the “L7805CV” voltage stabilizer work? Can you support your explanation using math to illustrate what is happening in this circuit? Here is a hint, you will have 9 volts entering the circuit, and only 5 volts going to the device through the USB connector. What happens to the other 4 volts?
   “L7805CV”稳压器如何工作？你能用数学来说明这条线路上发生了什么吗？提示：9伏电压进入电路，只有5伏电压通过USB接口进入设备，其他4伏电压会发生什么变化？
5. The cellphone charger circuit will work without the “diode” that is used it the “standard” and “advanced” circuit designs; however, the diode does have 2 very important roles that improve the design of this circuit. Can you identify one reason for including the diode? Provide evidence to support your claim?
   手机充电器电路将在没有“标准”和“高级”电路设计所使用的“二极管”的情况下工作；然而，二极管确实有两个非常重要的作用来改进电路的设计。那么为什么要用二极管呢？请解释。
6. The study of Ohms Law is an important aspect of most physics curriculums, and is a vital aspect of this project.
   欧姆定律是物理课程重要内容，也是本项目的重点。
   • Are resistors used in parallel or series in this circuit?
     在这个电路中，电阻是并联还是串联？
   • How does the total resistance of a circuit change if resistors are placed in parallel or series?
     并联或串联，电路的总电阻如何变化？
   • What is a voltage tree, and how is it used in this circuit?
     什么是电压树，它是如何在这个电路中使用的？
   • Based on the resistor values used in this circuit what is the output voltage of the “USB Data Ports”？
     基于此电路中使用的电阻值，“USB数据端口”的输出电压是多少？
   • How many amps / milliamps is this circuit? The voltage and resistance values are known.
     已知电压和电阻，那么这个电路的电流是多少安培/毫安？

DISCLAIMER: Sino-Exchange bears no responsibility for damages that may be caused to a devices as a result of a student testing their circuits. It is strongly advised that students to not connect their prototype circuits to their own devices, and all circuits should be checked by a teacher before being used.

Legal Disclaimer 免责声明

免责声明：对于因学生测试其电路而对设备造成的损坏，中外交流中心概不负责。强烈建议学生不要将其原型电路连接到自己的设备上，所有电路在使用前都应由老师事先检查。

NOTICE: many new phones will only work with authorized accessories that have special microchip that communicates data between the phone and charger; therefore this charger design will not work on some newer phone models. For example this design will work with the iPhone generation 5 or older.

注意：许多新手机只能与授权配件配合使用，这些配件配有特殊的微芯片，用于在手机和充电器之间传输数据；因此，这种充电器设计在一些较新的手机型号上不可行。例如，这种设计将适用于iPhone第5代或更低版本。

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Additional Resources

Please visit the ordering components guide for help with sourcing electrical components to use when implementing this project in your class. For additional project ideas you can the Electrical Circuit Design page which has an extensive list of possible project ideas that you can explore and use in your classes.