From smartphones, to smart lighting, to smart toys, numerous products employ light emitting diode (LED) components to enhance the end-user experience. With such a large variety of smart products utilizing LEDs, it’s useful to understand the technology behind LEDs, the types of LEDs commonly used and its’ various applications.
The technology
An LED is a small device typically used as a visual feedback for an event occurring in a system. It is a semiconductor device that emits visible light when an electric current passes through it. LEDs consist of two elements of processed material called P-type semiconductors (anode) and N-type semiconductors (cathode). These two elements are placed in direct contact, forming a region called the P-N junction (in this respect, the LED resembles a diode, although the LED has a transparent package, which allows visible light to pass through it). When a suitable voltage is applied to the LED, electrons immigrate from the cathode to the anode, releasing energy in the form of photons.
Different semiconductor materials have varying bandgaps that emit photons at different energy levels that determine the wavelength of the emitted light. Infrared and ultraviolet LEDs operate on the same principle, however the light they emit is not in the visible range of the spectrum.

Exactly the same technology is used in moderns displays. Tiny LEDs replace the tubes that light up HDTV displays to make dramatically thinner televisions.
Types of LEDs in smart products
LEDs are found in a wide range of size, colors and illumination intensity. There are four types of common LEDs:
- 1-Color LED – simple indication LED
- 2-Color LED – specifies two different modes using one LED
- 3-Color LED – specifies three different modes using one LED
- Multi-Color LED – for creates multiple shades of color; up to 256 shades.

LED Applications for the Internet of Things
The two basic applications of LEDs are indicator LEDs and illuminator LEDs. Indicator LEDs are usually inexpensive, low-power and suitable only as indicator lights in panel displays for electronic devices. Illuminator LEDs are durable, high-power devices that are capable of providing illumination.