How to Check an IR LED with a Multimeter

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You may be acquainted with what infrared LED is, but the possibilities are you are familiar with the devices where they are utilized. An infrared LED is a small lighting emitting diode utilized to power devices like remote controls. The wavelength delivered by infrared light brings a signal telling the devices what to do. For instance, it tells the remote to change the channel of the TV. 

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What is an Infrared LED? 

In case you didn’t know, infrared LEDs are solid-state light sources producing electromagnetic energy in the near-infrared part of the spectrum. Keep in mind that the emission wavelength is carefully coordinated to the response peak of phototransistors and silicon photodiodes. 

As you may already know, LEDs offer the perfect light source in various applications, particularly with their capability to emit light over a narrow bandwidth. That enables them to emit light that shows to be a single color. They also feature a very small size, low power consumption, long operating lifespan, and a low cost too. IR LEDs also provide the same benefits but function in the IR wavelength. 

IR LEDs are considered a special purpose light-emitting diode that emits an infrared signal. Particularly, it’s a semiconductor device releasing infrared rats every time it is exposed to electrical current. 

The working mechanism of an IR LED is quite straightforward. The electrons from the N area recombine with the remaining hole of the P region in a suitably created recombination region that lies in between the N and P-type region when the PN junction is forward biased. 

The recombination process in the infrared red region involves radiation of energy in the forms of photons. When liberated from the region, the photons might either be reabsorbed in the structure or may leave the surface or IR LED in the form of radiant energy. 

Uncovering the Power of Infrared LED

Did you know that light-emitting diodes at infrared wavelengths are considered the magic behind such things as optical communications and night vision? That also involves the streaming data that comes through Netflix. 

Infrared light-emitting diodes are composed of crystals of such materials as indium gallium arsenide. These can’t be grown on silicon-based of their various crystal structures.

You may be wondering what makes these LEDs different from the standard LEDs you find in your local hardware store. You will find some major differences between the visible LED light and infrared LEDs, particularly when we talk about their electrical qualities. 

For example, an IR LED features a lower forward voltage compared to what visible light LED does. On top of that, it features a greater rated current. That is because of their differences in the junction’s properties. An average infrared LED drive current may be as much as fifty milliamps. Hence, it is not smart to drop in a visible LED just to change a bad infrared LED. 

As mentioned, the LED infrared is utilized in remote controls. A more typical application of this is in security devices. That’s mainly because the light cannot be seen. Infrared lights are made with wavelengths ranging from 8330 to 959 nanometers. Bear in mind that that’s not the wavelength visible by the human eye. That makes the IR LEDs suitable for use with closed-circuit TV systems, alarm systems, video cameras, and even night vision products. 

Common Uses of Infrared LED in Daily Life 

Take note that the uses of infrared LEDs vary on their nanometers or wavelength. The most common usage varies between 808nm and 940nm. These devices are utilized in daily life in automated card readers and TV remote controllers. 

The usage of LEDs could be categorized into two kinds: reflecting and direct, and the way in which the infrared LED and the receiving diode contact identifies the uses of the LED. 

  • 808nm 

At the lower end of the infrared frequency, IR LEDs are normally utilized in non-visual applications but are also seen in security cameras. Medical lasers, solid-state lasers, and appliances work with this infrared frequency. 

  • 830nm 

At this range, infrared light is utilized for automated card readers at hotels and subways. 

  • 840nm to 870nm

IR LEDs are seen more typically in visual applications. Such LEDs are utilized in waterproof cameras and in both nighttime and daytime security cameras at crossroads and stores. Meanwhile, the non-visual application at this particular wavelength is normally seen in indoor phones and silent alarm systems. 

  • 940nm 

This is considered the highest infrared LED signal. This is the one often used by consumers. It’s the LED accountable for remote control’s functionality, including those utilized with DVD players and TVs. 

Further, wireless game controllers belong on the list as well. Any appliance using a remote control with infrared technology utilizes this LED signal. 

How Do You Check an IR LED? 

Here’s what you need to do if you like to check your IR LED with a digital multimeter.

  1. Set your digital multimeter allowing it to measure DC voltage, and make sure you turn it on.
  1. Hold your remote control near the IR diode and push any button.
  1. If your remote control is working, it means the voltage displayed on display will immediately increase. The voltage will drop again once you release the button. 

Do not expect a high voltage from your IR diode, though. The voltage produced by the diode will be approximately 300 millivolts. Nonetheless, that will be enough to determine whether the remote control is bad or not. 

Final Thoughts

Compared to LEDs that project components of the visible light spectrum. Infrared LEDs are not used to offer light. Instead, they are used in various signal transfer systems, like night-vision cameras, TVs, and other devices. 

Furthermore, an infrared LED beams light along with data signals to control the device. Hence, these LEDs are utilized in cameras, security installations, and other types of technologies. They are extremely practical and helpful due to their low heat production and low energy consumption. 

There you have it! We hope you find this guide informative and useful. Share your thoughts with us by leaving your comments below.

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