The Light Dependent Resistor works on the basic principle of photo conductivity, making them useful
in light sensing. The term photoconductivity stands for phenomenon in which the conductivity of a
substance increases while in contact with light. In general terms, the LDR is made up of substance
who has low conductivity in darkness, and whenever it comes in the contact with light the
conductive property of the sensor increases. A typical light dependent resistor has a resistance in the
darkness of 1MOhm, and in the brightness a resistance of a couple of KOhm.