physics investigatory project- LDR. IATION ‘N LDR CONCLUSION Based on the obsewation above, it eam be cometuded that the LDR based. INTRODUCTION • A light dependant resistor(LDR) or a photoresistor or photocell . Physics Investigatory Project on LDR as Variable Resistor. Project Report Submitted On Light Dependence Resistance  Submitted By: A. Varun Class â XII Kendriya Vidyalaya no. 2 Pondicherry.

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The advantage is that; we can dupe the intruder by using invisible light as the light rays will not be visible even in the night. Thus, lrr buzzer will start ringing. Keeping all the lamps at a fixed distance.

Photoresistor mechanism A photoresistor or photocell is proect component that uses a photoconductor between two contacts. 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. In project, we use carbon resistance of two kilo-ohms, ohms and ohms.

Physics Investigatory Project LIGHT DEPENDE Submitted by | Gopinath Sah –

Connections may be faulty. Distinction needs to be made here between photocells and LDRs. As a consequence, the collector current of T1 drives transistor T2 and T2 begins to fire. Theory Alight invetsigatory resistor works on the principle of photo conductivity.

There are two types of photoconductor and hence photoresistor: But the moment, the light source is interrupted, the buzzer will start ringing. Circuit Diagram Now, let us understand how the switching takes place when the LDR is illuminated by light. But when light falls on the LDR, the LDR starts conducting and the net base voltage of transistor T1 crosses the threshold voltage, causing T1 to fire.


USES It can be used in street lights. The result of this process is more and more current starts flowing through the device when the circuit is closed and hence it is said that the resistance of the device has been decreased. When no sufficient base voltage is present, the switch is off.

Connect the LDR, battery 6V and the multimeter in series. Behind the door, a light source is placed and in the line of vision of the light source, an LDR is also placed.

Light dependent resistor(LDR) – physics investigatory project

Aim a Dark sensor using L. By using buzzer, it can be used for security purposes in jails.

In frontier and pronect areas, people face many problems due to damaged street lights. Another end of the LDR is connected to the emitter. This is a rectangular prism shape with rounded edges and a polarized snap connector at the top. I would also like to express my gratitude to the staff of the Department of Physics at Kendriya Vidyalaya Pondicherry university campus for their support during the making of this project.

Page 21 of 23 Biblography 1. Should a need arise to destroy the project; care should be taken to dispose off the LDR properly as it contains harmful chemicals that can prouect the environment. The resistance of a photoresistor decreases with increasing incident light intensity; in other words, it exhibits photoconductivity.


This project is investigafory genuine and doesn’t not involve in any kind of plagiarism.

Investigtory can be used in hilly areas. It can be used in jail lights. Thus, when there is no light on the LDR, the transistor remains un-fired. A typical digital counter is shown in the accompanying picture. Repeat these steps with different power sources at different distances and note down observations. Photoresistors come in many types. Remember me on this computer.

Although we have used a low intensity laser, this can be harmful if aimed accidently at the eyes or if the reflected beam is seen through naked eye.

When a thin slice of p-type is sandwiched between two blocks of n-type, then n-p-n transistor is formed. At this time, it becomes earth, so that no voltage flows through the base of transistor T 1.

Physics Investigatory Project On LDR | Richard Parker –

Light Dependent Resistance [LDR] is a resistance, in which opposing power of current depends on the presence of quantity of light present, i. The LDR may not be perpendicular to the source. Choose a specific position for the source and mount it using a holder, make sure it is stable. In the project, we use relay of investigatofy ohms.