# Physics LDR

Topics: Semiconductor, Ohm's law, Incandescent light bulb Pages: 4 (939 words) Published: October 8, 2014
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LIGHT DEPENDENT RESISTANCE
INTRODUCTION
In the society, some times street lights glow in day time due to any reason. In mines area people face many difficulties due to absence of light in the nights. In frontier and hilly areas, people face many problems due to damaged street lights. For solve above these problems, we create a device in which the lights glow in night and in day time, they off automatically and don't glow. Due to use of it, we can solve above problems and can also save electricity and men's power. PRINCIPLE

This project is based on Light Dependent Resistance (L.D.R.). Light Dependent Resistance [LDR] is a resistance, in which opposing power of current depends on the presence of quantity of light present, i.e. the resistance of LDR increases or decreases, according to quantity of light which falls on it. If LDR places in darkness, the resistance of LDR increases and when light falls on it, the resistance of LDR decreases and act as a conductor. Any LDR in the presence of light and darkness changes its resistance is depends on the different types of LDR. ADVANTAGES

 Collection of parts of the circuit are easily available.  Accuracy of this circuit is more than accuracy of other circuits.  By using laser, it can be used for security purposes.
 It can be used to stop the wastage of electricity.
 The cost of circuit is low.
 This circuit saves the men's power.
USES
 It can be used in street lights.
 It can be used in mines areas.
 It can be used in hilly areas.
 By using laser, it can be used for safety purposes.
 It can be used in frontier areas.
 It can be used in houses.
 It can be used in jail lights.
BRIEF DISCRIPTION OF COM PONENTS
1. TRANSISTOR:-When a thin slice of p-type is sandwiched between two blocks of n-type, then n-p-n transistor is formed. It consists of emitter, base, and collector. In the project, common emitter n-p-n transistor ( BC-147 & SL-100) is used. 2. DIODE:- When a p-type and...