DESCRIPTION OF COMPONENTS

• IC 555: The 555 timer contains over 23 transistors , 16 resistors and two diodes. The IC 555 timer relies upon an external capacitor to determine the off-on time intervals of the output pulses. The IC 555 timer cannot create a pulse by itself. The details of this integrated chip are provided in a later section.

• Light Emitting Diode (LED) : LED is a p-n junction diode which emits light when forward biased. When a suitable voltage is applied to the leads, electrons are able to recombine with electron holes within the device, releasing energy in the form of photons.

Circuit Symbol :

The LED consists of a chip of semiconducting material doped with impurities to create a

p-n junction. When an electron meets a hole, it falls into a lower energy level and releases energy in the form of a photon. The wavelength of the light emitted, and thus its colour, depends on the band gap energy of the materials forming the p-n junction. Their threshold voltage is 1.6Volts to 2.4Volts.Unlike incandescent light bulbs ,LEDs never burn out.

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DESCRIPTION OF COMPONENTSResistor: A resistor is a two-terminal electrical component that implements electrical resistance as a

circuit element. Resistors act to reduce current flow, and at the same time, act to lower voltage levels within circuits. The resistors used in this circuit are carbon composition resistors.

Circuit Symbol:

Capacitor: A Capacitor consists of two conductors that are separated by an insulator. It is a two-terminal electrical component used to store energy electrostatically in an electric field. When there is a potential difference across the conductors, an electric field develops across the dielectric, causing positive charge to collect on one plate and negative charge to collect on the other plate.

Circuit Symbol:

Battery: An electric battery is a device consisting of one or more electrochemical cells that convert stored chemical energy into electrical energy. Each cell contains a positive terminal and a negative terminal.

Circuit Symbol:

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Working Circuit

I would like to express sincere gratitude to my teacher Mrs. Rekha L Shastry as well as our principal Mrs. Mamatha Raviprakash for providing an opportunity to carry out a project “Do you conduct electricity?” which has helped me to acquire a lot of knowledge . I would also like to thank our laboratory assistant, Mr. Dinesh , my friends and parents who have helped me a lot in finalizing this project within the limited time frame.

ACKNOWLEDGEMENT

INDEXSl.No. Content Page No.

1 Objective 1

2 Introduction 2

3 Materials required 3

4 Circuit Diagram 4

5Description of Components

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6Construction of the

Circuit7

7 Working of the Circuit 8

8 Observations 9

9 Conclusions 11

10 Working circuit 12

11 Bibliography 13

BIBLIOGRAPHY

1.Basic Electronics by Suyash Dake

2. NCERT Lab Manual

3.www.Google.com

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