简单的LED电路

In this post we will learn how to build a few interesting LED circuits, and also learn how to connect LEDs correctly in a circuit.

LED代表光发射二极管，实际上是一个半导体二极管，具有发射光的特性，当电流朝正确的方向通过它，或者当LED向前偏置时。

LED有两个用于连接电路的端子。由于LED基本上是二极管，因此其末端具有阳极和阴极形式的极性。

The anode terminal is supposed to be connected with the positive supply, and the cathode to a negative supply.

通常，LED可以耐受的最大电压为3.5 V，但是3.3 V是大多数标准LED建议使用的最佳值。

LED电阻

Although an LED is a diode, it's highly sensitive to current, and cannot tolerate anything exceeding its specified range.

In order to ensure that an LED is safe from an over-current situation, a calculated resistor is normally added in series with one of the terminals of the LED. This resistor may be connected in series with either the cathode terminal or the anode terminal of the LED.

This current limiting resistor can be simply calculated using the following formula:

R = Input Supply - LED Voltage rating / LED max current.

例如，假设LED的正向电压额定值为3.3 V，最大电流极限为20 mA（0.02 AMP），然后假设输入电源为6 V，则可以按以下方式计算串联限制电阻的值：

r = 6-3.3 / 0.02 = 135欧姆，最近的安全可用值为150欧姆。

How to Connect an LED

Connecting an LED to a supply DC, for getting an optimal illumination, is very easy. A simple connection diagram can be seen in the following image, which is applicable to all LEDs. The current limiting resistor must be calculated as explained in the above paragraphs.

Here, the shorter terminal which is the cathode goes to the negative supply input, while the longer terminal which is the anode pin of the LED is connected with the positive input of the DC supply through a limiting resistor.

Application Circuits

LED令人着迷，因为这些设备能够按照给定的应用程序产生不同颜色的强大光输出。

LEDs can be used for making plenty of eye catching ornamental or indicator circuits for many useful purposes.

Without further ado, let's take a look at a few interesting LED application circuits as presented in the following paragraphs.

Smallest LED Flasher

Flashing LED indicator look very attractive but the design can be more interesting if the circuit uses the least number of parts. The following circuit shows how a single LED can be configured with a single transistor to create a reliable flashing LED indicator.

有关此电路的更多信息，您可以参考this article.

Random LED Flashing Light for Christmas Tree

LED设备的最佳用途是它们能够根据用户所需的任何内容进行装饰。以下电路显示了如何将单个IC 4060用于构建多个LED闪存器电路，如下图所示。所有连接的LED字符串将根据P1锅的调整或电容器C1的值的调整，以不同的随机速率闪烁并闪烁。它用于装饰圣诞树或申请在偶像周围制作一条闪烁的LED项链。

Full description of the design is provided在本文中。

LED Rotating Light

如果您有兴趣在不使用灯的旋转机构的情况下建立旋转的警察或救护车效果，那么以下电路可以帮助您。

该电路中使用的LED是1瓦的LED，它将产生缓慢的交替照明和褪色，从而产生旋转的LED灯光效果。

可以找到有关电路的更多信息在本文中。

LED背光铭牌

The following image shows an example of how an attractive back light illuminated LED name plate circuit can be built using just 4 LEDs attached horizontally at the 4 corners of the nameplate, internally.

有关此的更多信息，可以阅读完整的建筑过程in this article

LED立方体电路

要构建LED立方体灯，您将需要一个塑料立方体，一堆LED和级联延迟电路。对于每个LED，使用了两个电路上的两个晶体管延迟，并且电路上的许多延迟相互级联，具体取决于LED的数量，形成了一个长延迟链，从头到尾循环。当施加电源时，LED开始一一打开，直到立方体上安装的所有LED都点亮。在所有LED亮起后，反向发生，LED逐一关闭，并且周期不断重复。

可以找到电路的细节in this article

水位表

LED也可用于指示水箱中的水水平。为此，我们需要一些LED一些晶体管和电阻。可以在下图中看到完整的设计。

When the water bridges the contacts (A to D), between the transistor base resistors and the positive supply, the respective LEDs illuminate in succession, indicating the rising level of the water.

More on this can be learned fromthis article.

简单的连续性测试

仅需几个晶体管以及LED即可制作简单的连续性测试仪电路。该电路可用于测试变压器，电线束或具有复杂接线系统的任何电气系统的连续性。

在这种连续性测试仪配置中，当线束的一端用一只手接触到正面供应，然后将另一只手固定在正供应上，然后触摸1m电阻端，而导线的另一端表示导线束的连续性

可以学到更多this article.

In the above article we discussed a few interesting LED circuits, but this might be just the tip of the iceberg, since there are innumerable more circuits that can be designed using LEDs for getting fascinating lighting effects or for useful indication purposes.

If you are interested to investigate more LED circuits, you can refer to the following link:

DIY LED Projects