Light sensitivity sensor - LDR

We know how resistor works right? Let's go back to Chapter 3, Components and Connections for a quick recap and come back here. It essentially restricts the flow of electrons in a circuit. Light Depended Resistor is a special kind of resistor that reduces its resistance when light falls on it. How does that work you ask? Good question.

Let's dig a little deeper into what is LDR and how it works. First of all, this is how the symbol of LDR looks like:

  

(Image source: https://cdn.instructables.com/F1H/DRCQ/IDCXJLG6/F1HDRCQIDCXJLG6.MEDIUM.jpg)

Symbol:

The arrow signs coming down show the light falling on the LDR. You know what everything in the world is made up of right? Remember we learnt about electrons in the beginning of the book? Electrons are the fundamental part of any material.

Let's start from there. So similar to electrons, photons are fundamental part of light. Light is not made up of only particles though, it has waves too (I know right? We think we...