Light Dependant Resistor

A photoresistor or light dependent resistor is a component that is sensitive to light. When light falls upon it then the resistance changes. Values of the resistance of the LDR may change over many orders of magnitude the value of the resistance falling as the level of light increases.A photoresistor is an active component that decreases resistance with respect to receiving luminosity on the component's sensitive surface. The resistance of a photoresistor decreases with increase in incident light intensity; in other words, it exhibits photoconductivity.

Advantages Of Light Dependant Resistors

An Acronym for a Light Dependant Resistor is LDR

How many types of LDR are there?

Two types.Based on the materials used, photo resistors can be divided into two types:

  1. Intrinsic - In intrinsic photoresistors, the active material is made of pure semiconductor materials, such as silicon or germanium.
  2. Extrinsic - Extrinsic photoresistors are the more common choice and are made from extrinsic-type semiconductor materials, i.e. semiconductor materials which have been doped with other atoms with a higher number of valence electrons—commonly phosphorus.