What is the light dependent resistor and how does it work?
A Light Dependent Resistor (LDR) is also called a photoresistor or a cadmium sulfide (CdS) cell. It is basically a photocell that works on the principle of photoconductivity. The passive component is basically a resistor whose resistance value decreases when the intensity of light decreases.
What is the function of light dependent resistor?
A photoresistor (also known as a light-dependent resistor, LDR, or photo-conductive cell) is a passive component that decreases resistance with respect to receiving luminosity (light) on the component’s sensitive surface.
What is LDR principle?
The working principle of an LDR is photoconductivity, which is nothing but an optical phenomenon. When the light is absorbed by the material then the conductivity of the material enhances. When the light falls on the LDR, then the electrons in the valence band of the material are eager to the conduction band.
Which material is used in LDR?
As its name implies, the Light Dependent Resistor (LDR) is made from a piece of exposed semiconductor material such as cadmium sulphide that changes its electrical resistance from several thousand Ohms in the dark to only a few hundred Ohms when light falls upon it by creating hole-electron pairs in the material.
Why CDS is used in LDR?
Cadmium sulphide is used in the manufacture of photoconductive cells because its spectral response curve closely matches that of the human eye and can even be controlled using a simple torch as a light source.
What is light dependent resistor and its applications?
Light-dependent resistors are simple and low-cost devices. These devices are used where there is a need to sense the presence and absence of light is necessary. These resistors are used as light sensors and the applications of LDR mainly include alarm clocks, street lights, light intensity meters, burglar alarm circuits.
What does light dependent resistor mean?
LDR stands for Light Dependent Resistor or Photoresistor, which is a passive electronic component , basically a resistor which has a resistance that varies depending of the light intensity.
What is the purpose the light dependent resistor?
A photoresistor, often referred to as a light dependent resistor, is a resistor that reacts to increased exposure to light by decreasing its resistance in a circuit. They are used in a variety of devices that require sensitivity to light to operate, such as glow-in-the-dark watches and streetlamps that turn on when the sun goes down.
How do light dependant resistor(LDR) works?
A photoresistor or light dependent resistor is an electronic 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.