Introduction to LED | Complete Guide to IoT

In this article I will introduce you one one most used component in IoT practicals the LED. Why we use LED in IoT projects mostly. Types of LED and How to identify the polarity of LED.

Every project in IoT starts with LED why?

Because LED is easy to control, consumes less power, do not require extra library to drive it, the code is very simple, do not require any extra circuit to drive it. Also we can detect the brightness is easily by our eyes it means if two LED is glowing at different brightness then they can be easy detected, thar is not in case of moving shaft of motor or any other electronics. Hence LED is used as a starting project for IoT.

What is Led ?

LED is also known as Light Emitting Diode you will learn about diode in your class 12th but let me explain basic of LED here so that you will find easy to work with our upcoming articles.

LED is a diode which is made up of a material known as semiconductor (A material that has an conductivity between a conductor, such as copper, and an insulator, such as glass) it emits visible light when current is passed through it . The color of the light emitted depends on the energy lost or the energy required by the electron to cross the band gap to combine with the hole.

LEDs have huge advantage over other light source as I have already told you that they consume less power also they are cheap, and small in size yet more light producing.

Types

There are many different types and colors of LED they are manufactured for various applications. We will use some of them in our next project

How to use LED

Power sources

If you know about diode you must be knowing that current in diode rises exponentially with respect to applied voltage. So a minor change in the applied voltage can cause a large current inside the LED hence damaging the LED. So it is advised to use resister in series with the LED to prevent it from damaging.

Use a register(generally 1K ohm) in series with the LED to prevent it from damaging

Electrical polarity

Since LED is a diode and diode works only in forward bias so LED will only function when forward potential is applied. Nothing will happen if reverse potential is applied but if the reverse potential is large enough hence it will cross breakdown voltage and the diode or LED will burn.

So to avoid the reverse current must be limited or use the LED in forward bias with register in series.

Here we will show how to connect the LED to a battery or a potential in forward bias because it only works in forward bias and emits light.

How to recognize which terminal will be connected where, Most of the LED will have two terminal one of them is Cathode and other is Anode or one of the terminal is larger than other or if you see inside the glass coating the LED consist of two components one is slightly bigger than other or you can say one has a cup type of structure which have semiconductor die.

To glow LED it is connected in forward bias.

p side of diode is connected to positive n side of diode is connected to negative.

or anode is connected to positive terminal of battery and cathode is connected to negative terminal of the battery.

LED’s terminals do not have equal length so longer terminal is connected to positive terminal of battery and shorter terminal of led is connected to negative terminal of the battery

Notice the anode and cathode terminal

or the terminal which have cup shape (having semiconductor die) and is large part inside the glass case is connected to negative terminal of batter and smaller part inside the glass case is connected to positive terminal of the battery.

or the flat spot you can notice in above both pictures the flat side of terminal is connected to negative of battery and non flat is connected to positive of battery.

So just now I have told you five ways to recognize the terminals of the LED and connect it suitably to the battery to glow the led. If you connect led in reverse manner nothing will happen the LED wont glow. The only thing which you have to do before connecting led to a battery is to connect a resister in series so that high current will not damage the LED.

Advantages

• Efficient
• Large Color Range
• Small Size
• Less Startup time
• Faster ON OFF Cycle
• Brightness Control
• Very Less failure
• Large Lifetime
• Shock Proof

Disadvantages

• Temperature dependent
• Sensitive towards minor Voltage Change
• Light pollution
• Efficiency droop with current
• Impact on wildlife
• Thermal runaway:

So today in this article we got to know a lot of things about LED's and how to connect them. In our upcoming articles you will be making your first IoT project and many more so stay tuned, keep visiting

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In the next article you will make your first IoT project. Till then KEEP LEARNING