Physics Project Report 2

PHYSICS PROJECT REPORT

2013-2014

SUBODH PUBLIC SCHOOL

SUBMITTED BY: GUIDED BY:SPARSH DUTTA MRS.AJAYSHREESHARMA

S-2A H.O.D(PHYSICS)

ROLL NO: S-3822

CERTIFICATE OF AUTHENTICITY

This is to certify that SPARSH DUTTA, a student of class XII has successfully completed the project report on the topic: ‘’IR Security Sensor Using A Full Wave Rectifier Circuit’’ under the guidance of Mrs. Ajayshree Sharma (Subject Teacher).

This project is absolutely genuine and does not indulge in plagiarism of any kind. The references taken in making this project have been declared at the end of this report.

Signature ( Subject Teacher) Signature ( Examiner)

ACKNOWLEGDEMENT

The project could have never been possible without the support of various sources. It is extremely impossible to thank every individual who has helped me in completing this project. Some people have helped in the basic formularization and there were sources that helped me in giving the ideas a physical form/shape. I am extremely grateful to my teacher, Mrs. Ajayshree Sharma, for his invaluable guidance in the project right from the beginning. Her vital support helped the project to take a logical and suitable shape.

I take this opportunity to thank the School authorities, for extending their full support and cooperation in the project.

Last but not the least; I would like to thank everyone who has offered a helping hand when required.

INTRODUCTION

The IR Security Sensor Using A Full Wave Rectifier Circuit can be of great use in day to day life. The device for the circuit uses a full wave rectifier circuit which is used to rectify all the alternating current components from A.C Mains into direct current. The two alternating halves of an alternating current are rectified in full wave rectifier circuit which is advantage over half wave rectifier. Most electronic circuit cannot withstand such a huge amount of power which is coming from A.C Mains.

Therefore this rectifier circuit has a lot of employment in day to day life.

MATERIAL REQUIRED

Connecting Wires Plywood A Transformer A Capacitor L.E.Ds P-N Junction Diodes Insulating Tapes Solder Machine, Solder Wax and Flux IR Security Sensor Resistors A Plug Wire -1M A Toy Car For Demonstration

DETAILS OF MATERIAL REQUIRED

Connecting wires and a plug - A normal insulated copper wire able to withstand 230 – 250 v is required.

Single lead wire - Thin wire with one single strand of copper well Insulated and able to conduct a current of 1 ampere or a D.C current efficiently.

A circuit board -A normal board of mica facilitated with clips to simplify the connection.

A small box - To place the equipments safely.

A bulb - To test the output voltage whether Direct or not.

A 6-0-6 transformer-Transformer is a device used to change the voltage of an alternating current. The transformer which converts low voltage to high voltage is called a step up transformer whereas the one which converts high voltage to low voltage is called a step down transformer. It consists of a laminated core consisting of two coils, a primary & a secondary coil. In a step up the number of turns in the secondary is greater that that of the primary and the reverse in a step down transformer. Here

we use a step down transformer which steps down 230V to 6V between the secondary terminals and the center tap.

A CAPACITOR-The ability of a metal to store electric charges measures the capacitances of a conductor. It provides high impedance to Alternating Current and stores them while all the D.C components are let to pass. There are different types of capacitors –o PARALLEL PLATE CAPACITORo SPHERICAL CAPACITORo CYLINDRICLAL CAPACITOR

Here we use capacitor of 1000 m F & 25 v.

A Resistor - A resistor is an electronic components whose resistance value tells us about the opposition it offers to the flow of electric current. Resistance is measured in ohms.

P-N junction Diodes -When one side of a semiconductor crystal (Germanium or silicon) is doped with acceptor impurity atoms and the other side with donor impurity atoms a P-N junction is formed. It is also called semiconductor or crystal diode. When diffusion of the two regions occur a resultant potential barrier is created between the two sides due to migration of electrons and holes. When the diode is connected with P side to positive terminal of a battery & N side to –ve terminal it is said to be forward biased & reverse biased when reversed. In forward biasing the applied positive potential repels the holes and turns a current is made to flow overcoming the Internal potential Barrier. While in reverse biasing the –ve electrons 1st attract the holes and widen the Barrier and

then only the repulsion between the inner electrons occur and current flows. So theoretically no current flowsthrough due to the widening of the Potential barrier but practically a verysmall current does flows through.Different types of diodes are present –

Zener diode P-N junction diode LED LAD Solar cell

Here we use a P-N junction diode. The grayish ring indicated the N side and the Black colouration the P side.Finally, small equipments such as a soldering iron to solder the lead, Blades, holders, insulation tapes – to insulate the wire from shocking and sand paper – to rub the oxidized wire ends are used.

IR SENSOR- This Sensor is having two diodes in which continuos current is flowing and one diode is acting as a thrower of infrared waves and other is receiver of infrared waves.

CONNECTION DETAILS

Connections are done as in the circuit. The A.C. supply is given to both the input wires of the transformer and the two ends of the secondary coil is given to the P side of the two diodes and the N side of the diodes are twined and then connected to one end of the Capacitor and the other end to the center tap lead and to the resistor.Further, the other end of capacitor with the diode connection is connected to the other end of the resistor.

WORKING1st when the A.C. is supplied to the transformer, it steps down the220V main supply to 6 volts. It has a capability of delivering a currentof 500mA. The 6 volts A.C. appearing across the secondary is theRMS value and the peak value is 8.4 volts. During the 1st half cycle of the A.C. input Diode D1 is forward biased and a current ‘I’ flows in the circuit in the direction S1D1ABEOS1. During this time diode D2 is reverse biased. So it does not conduct any electric current. During the next half cycle the diode D2 is forward and D1 is reversed. Hence D2 conducts current in the direction S2D2ABEOS2 and D1 does not conduct any current. In subsequent half cycles of the A.C current the above processes are repeated. In both the half cycles it is clear that current flows through the resistor in only one direction ABE. Even though the voltage across RL is unidirectional it will still contain a few A.C components. This is filtered and made smooth using a capacitor, which filters 99% of the A.C current. A resistor is then used to adjust the output voltage. We can then test the o/p Voltage using a multi-meter.By the use of more number of diodes the efficiency can be increase toa maximum of 94.6%. Here we only use 2 diodes. The use of multiple capacitors also nearly filters all A.C components from the supply and resistance is adjusted for the required output. As this is a simple circuit, only one capacitor and a resistance is being used. But there will be slight factor of A.C. current still left in the output but it is negligible.

RECTIFIED D.C VOLTAGE

PHOTO GALLERY

PHOTO GALLERY

BIBILIOGRAPHY

1) Electronic projects Blog for beginners by A.K Manini 2) H.C VERMA XIIth3) S.L ARORA PHYSICS XIIth4) NCERT based CBSE text for XIIth5) Website: www.Google.com

THANKS TO ALL.