LED drop

August 17, 2025

Guide: I believe that everyone is familiar with LEDs. In fact, LEDs are a type of semiconductor diode that converts electrical energy into light. Let me explain the voltage drop of LEDs for you. If you're not sure about what it means, let's take a closer look together!

1. What is LED Voltage Drop â€“ An Introduction

Light-Emitting Diodes, commonly known as LEDs, are semiconductor devices that emit light when an electric current passes through them. They were first developed in 1962 and initially emitted only low-intensity red light, mainly used as indicator lights by companies like HP. Over time, advancements led to the development of LEDs that could emit various colors, including visible, infrared, and ultraviolet light. Today, LEDs are widely used not just as indicators but also in displays, lighting systems, and even in general illumination thanks to the invention of white LEDs.

2. How Is LED Voltage Drop Produced?

An LED can be thought of as a constant voltage load. The voltage drop across an LED depends on the energy barrier that photons must overcome during emission. This energy barrier is determined by the color of the light emitted, which means the voltage drop varies depending on the color. Since manufacturing processes may result in slight differences in wavelength, the voltage drop can also vary slightly from one LED to anotherâ€”typically within Â±10%. When designing an LED driver circuit, a common mistake is to base the design on the typical forward voltage value. However, this approach can lead to issues if multiple LED strings are connected in parallel. For example, a single 1W Luxeon Star white LED has a typical forward voltage of 3.42V, but actual values can range from 2.79V to 3.99V, resulting in a deviation of up to Â±15% or more.

3. LED Voltage Drop

The voltage drop of LEDs varies depending on the type and material used. Here are some typical values: - **Red LED**: 2.0â€“2.2V - **Yellow LED**: 1.8â€“2.0V - **Green LED**: 3.0â€“3.2V For standard operation, the rated current is usually around 20 mA. For **SMD LEDs**, the voltage drops are slightly different: - **Red LED**: 1.82â€“1.88V (current: 5â€“8mA) - **Green LED**: 1.75â€“1.82V (current: 3â€“5mA) - **Orange LED**: 1.7â€“1.8V (current: 3â€“5mA) - **Blue LED**: 3.1â€“3.3V (current: 8â€“10mA) - **White LED**: 3.0â€“3.2V (current: 10â€“15mA) The voltage drop depends on the materials used and the specific wavelength of the light emitted. Additionally, temperature variations between LEDs can affect both color and voltage drop.

Understanding the voltage drop of LEDs is essential for proper circuit design and ensuring consistent performance. Whether you're working on a simple project or a large-scale lighting system, knowing these details can help you avoid common pitfalls and improve efficiency.