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LEDs - Circuit Board Indicators, Arrays, Light Bars, Bar Graphs

LEDs, or light emitting diodes, are among the most popular electronic components and can be found in a wide range of electronic applications. Specifically, LEDs are used as circuit board indicators, arrays, light bars and bar graphs. Data and power features of these components are indicated with a variety of colors and intensities, depending on the application. But before delving into the particular application fields and working principles it is important to first understand the basic characteristics of LEDs.

LEDs are composed of semiconductor materials and utilize the flow of electrons to produce light. All LEDs have three parts: the anode is the positive side, the cathode is the negative side and the semiconductor layer, called the “junction”, is sandwiched between the anode and cathode. When sourced with electricity, the anode is positively charged and the cathode is negatively charged. Electrons flow out of the anode, through the junction and back into the cathode. In the junction, the electrons interact with the semiconductor material and create energy. Specifically, when the electrons and holes (the absence of an electron at the junction) combine in the semiconductor, photons – or energy in the form of light – is produced. This process is called “electroluminescence”.

LEDs are primarily used as indicators, arrays, light bars and bar graphs. Common uses of circuit board indicators are as power on/off lights, warning indicators and keypad indicators on electronic device control boards. Power indicators indicate either AC power or DC power with a single LED. Warning indicators are often found on commercial and industrial equipment and can also be varied in color and intensity depending on the type of warning. Keypad indicators are usually used on remote control devices. LED arrays are typically used as indicators and can produce a variety of colors, intensities and blinking effects. LED light bars and bar graphs use many LEDs in combination to create a certain effect. LED light bars are commonly used as indicators to show the level of a particular parameter, such as pressure, temperature or voltage. Bar graphs are often used to display quantitative values, such as how close a particular parameter is to its set point or maximum level.

LEDs can be controlled by two basic methods: current-mode or voltage-mode control. Current-mode control utilizes a series of resistors to limit the current flow through the LED. This method is most often used in simple indicator applications. Voltage-mode control is generally more efficient than current-mode control, as it uses voltage to limit the current flow. This method is used when more complex applications require precise control of the LED’s light output.

LEDs are becoming increasingly popular in a variety of applications. As the technology continues to evolve and become more advanced, LEDs are becoming more cost-effective and are replacing traditional light sources in many applications. While there are many different types of LED components and applications, the basic principles of LED usage remain the same. Understanding LED characteristics and how to control the light output is crucial for producing the desired results with LEDs.