Sohail Ansari

Home » Electronics » Light Dependent Resistor (LDR) & its Application

Light Dependent Resistor (LDR) & its Application

Blog Popularity

  • 156,450 hits

Enter your email address to follow this blog and receive notifications of new posts by email.

Archives

Recent Posts

Contact-


It stands for Light Dependent Resistor or Photo-resistor, which is a passive electronic component, basically a resistor which has a resistance that varies depending of the light intensity. A photoresistor is made of a high resistance semiconductor that absorbs photons and based on the quantity and frequency of the absorbed photons the semiconductor material give bound electrons enough energy to jump into the conduction band. The resulting free electrons conduct electricity resulting in lowering resistance of the photoresistor. The number of electrons is dependent of the photons frequency.

Untitled-1

Application :

As a switch : The most obvious application for an LDR is to automatically turn on a light at certain light level. For example

ldr_example

The circuit shown right shows a simple way of constructing a circuit that turns on when it goes dark.The increase in resistance of the LDR in relation to the other resistor which is fixed as the light intensity drops will cause the transistor to turn on.The value of the fixed resistor will depend on the LDR used, the transistor used and the supply voltage.

If we connect LED as a load then it will turn on in dark and turn off in presence of light. In this way we can use LDR in a various ways.If you have any other application then please reply below.

Email id: er.sohail.ansaari@gmail.com
          2007.ansari@gmail.com
Facebook id:https://www.facebook.com/sohail.ansari.itm
linkedin id:http://in.linkedin.com/pub/sohail-ansari/73/17a/547/

 

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: