What is LDR or Light Dependent Resistor

Light Dependent Resistor or LDR is a resistor that changes its resistance due to the intensity of light absorbed. LDR is also a resistor having a negative temperature coefficient, where the resistance is affected by light intensity.
 LDR or Light Dependent Resistor formed from cadium Sulfied (CDS) generated from ceramic powders.

In general, CDS also called conductive photo equipment, as long as the conductivity or resistance of CDS varies with light intensity. If the received light intensity is high then the barriers will also result in a high-voltage out also to be high and vice versa if the voltage is low. This is where the mechanism of the process of changing light into electricity occurs.

What is LDR or Light Dependent Resistor

CDS does not have the same sensitivity at each wavelength from ultraviolet up to infrared. This is called the characteristic spectrum and the response given by the manufacturer. CDS are widely used in planning a series of alternating (AC) compared with photo transistors and photo diodes.