LDR (Light Dependent Resister): Explained.

 

Light Dependent Resistor (LDR) :

            In this blog, we're going to be talking about a light-dependent resistor otherwise known as the LDR or a photoresistor. There are many different types of photoresistors but they will generally have some kind of look. The clue as to what they do is reflected in its name. It is a resistor that is light-dependent and what that means is that this is a resistor that changes its resistance depending on the amount of light that hits it.

Constituents:

They are made from a semiconductor material so that when light hits the semiconductor material it becomes more conductive and therefore has less resistance. If we attach this LDR with a multi-meter so we will be measuring the resistance across it. If we are in the kilo-ohms range, you can see that this resistor will have a resistance of 2-kilo ohms. If we give light to it, we will notice that its resistance drops below the range of the multimeter. So if we adjust the range of the multimeter, we can see now that the resistor has a resistance of under 1-kilo ohm. As we will move the light-dependent resistor closer and closer to the light source, we will notice that the resistance drops and as we will pull it away from the light source, the resistance starts to increase again. Now as we cover the LDR, we will return again to the 2-kilo ohms range of the multi-meter. Now if we cover this LDR, we will notice that the resistance will climb up to over 150 kilos. This is very high resistance. The darker the environment that this LDR experiences, the higher its resistance becomes.

Practical Uses of LDR:

Now we have covered that what an LDR is and the basic principle of how they work you may be asking what are the practical uses of LDRs and how can they be used within a circuit. Well LDRs or light-dependent resistors are generally used in applications where light is an important factor to the device it's being used in need to know when its light or dark outside so that they know when to turn on and when to turn off. They are also used as light meters in cameras. They can also be used as the light detector for an alarm, night lights, and many other things basically if we need to control something with light then an LDR is one of the most common ways that we can do that.

 

 

Hope that this article will cover the LDR.

Stay tuned as more interesting things are coming.

Bye.