Light Dependent Resistor (LDR)

Electronics always do some automatic things that make you look like there is magic or animal interference. But this is not possible in reality. Pressing a switch activates hundreds of computer software in an instant. Robots are answering thousands of your questions. There are so many devices around us. Some of them are constantly keeping you informed of your feelings. This revolution of technology is advancing at an unstoppable pace.

But all this is not happening with the help of magic or soul. Everything is possible through the controlled movement of electrons in the complex circuits of electronics. At the same time, the number of components in electronics is also increasing.

An important component of this electronics is the LDR or Light Dependent Resistor. Although its work is like a normal register, it has made many complex tasks easier through some differences. Normal resistors provide a certain amount resistance to current flow in a circuit in any situation. But LDR is a register whose resistance depends on the given incident of light. That is, when it is in the dark, its resistance is much higher. Too much block the flow. But when light is cast on it, its resistance decreases. When the intensity of light incident on the LDR increases, then the resistance decreases. Which is shown through the chart.

With this common feature of LDR we can accomplish many of our daily tasks without our intervention. Some of the works include-

  1. Automatic street lights.
  2. Automatic solar cell.
  3. Automatic fridge door close or alarm.

It is not a complex electronics. But in order to work more advanced in electronics, the idea of ​​these small components has to be kept in mind like an algebraic formula.


Jeion Ahmed
Electrical and Electronic Engineering (EEE)

Chittagong University of Engineering and Technology (CUET)

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