A

PROJECT REPORT

ON

“LAPTOP AUDIO AMPLIFIER”

SUBMITTED IN PARTIAL FULLFILMENT FOR THE AWARD OF DEGREE OF

BACHLOR OF ENGINEERING

IN

ELECTRONIC AND ENGINEERING

GUIDED BY: SUBMITTED BY :

Mr.Sugreev ASHUTOSH JANGID

ANUJ MALIK

ASHUTOSH TIWARI

DEPARTMENT OF FIRST YEAR

POORNIMA INSTITUTE OF ENGINEERING AND TECHNOLOGY

ISI 6 RIICO INDUSTRIAL AREA,GONER ROAD,SITAPURA

JAIPUR-302020 (Raj.)

INDEX

S NO. CONTENT PAGE NO.

1. CERTIFICATE

2. AKNOWLEDGEMENT

3. INTRODUCTION

4. COMPONENETS USED

5. CIRCUIT DIAGRAM

6. BIBLIOGRAPHY

DEPARTMENT OF ELECTICAL ENGINEERING

POORNIMA INSTITUTE OF ENGINEERING AND TECHNOLOGY

JAIPUR-302022

………………………………………………………………………………………………………

CERTIFICATE

This is to certfy that the project entitled “LAPTOP AUDIO AMPLIFIER” has been carried out by under my guidance on partial fulfillment of the degree of bachelor of engineering in electrical engineering in university of rajasthan ,Jaipur. During the academic year 2011-2012. To the best of my knowledge and belief this work is not been submitted elsewhere for the award of any other degree. The work has been found satisfactory and is approved for submission.

CIRCUIT DIAGRAM

INTRODUCTIONUsually, the audio output from a laptop’s built-in speakers is low. A power amplifier is required to get a high volume. Here is a simple circuit to amplify the laptop’s audio output.

The circuit is built around power amplifier IC LA 4440 (IC1) and a few other components. LA4440 is a dual channel audio power amplifier. It has low distortion over a wide range of low to high frequencies with good channel separation. Inbuilt dual channels enable it for stereo and bridge amplifier applications.

In dual mode LA4440 gives 6 watts per channel and in bridge mode 19- watt output. It has ripple rejection of 46 dB. The audio effect can be realised by using two 6-watt speakers. Connect pins 2, 6 and ground of IC1 to the stereo jack which is to be used with the laptop.

Assemble the circuit on a general-purpose PCB and enclose in a suitable cabinet. The circuit works off regulated 12V power supply. It is recommended to use audio input socket in the circuit board. Use a proper heat-sink for LA4440.

AKNOWLEDGEMENT

The satisfaction that accompanies that the successful completion of any task would be incomplete without the mention of people whose ceaseless cooperation made it possible, whose constant guidance and encouragement crown all efforts with success.

We are grateful to our project guides Mr.Sugreev Chaudhary and Mr.Rakesh Mathur(Senior Faculty) for the guidance, inspiration and constructive suggestions that helpful us in the preparation of this project.

COMPONENTS USED

1. IC(LA4440)2. LM 3243. SPEAKERS(6Ω,4W)4. LED (GREEN)5. RESISTOR (330Ω)6. CAPACITOR (2200µF,110µF,0.1 µF)7. DIODE8. Transformer (12-0-12)

IC(LA4440):

It has good ripple rejection of 46dB, small residual noise, built in over voltage and surge voltage protection etc. ideal feature of the IC is its pin-to-pin protection. Here LA4440 is wired in Stereo configuration using both inputs and outputs.

Features of LA4440

1. Built in two channels to use as Mono and Stereo2. Dual mode 6W x 2 and Bridge mode 19W3. 46 dB Ripple rejection4. 18V Max. Power handling and 12V typical5. Good channel separation and low distortion6. Built in Audio Muting function and Pin-to-Pin protection7. Surge protection circuitry

RESISTOR (220 ohm):

Red, red, brown, silver tolerance band: 22 x 10 = 220 ohms (220 ohms), with a tolerance of 10%.

CAPACITOR (2200uf, 110uf,0.1 uf):

A capacitor is a passive electronic component consisting of a pair of conductors separated by a dielectric (insulator). When there is a potential difference (voltage) across the conductors, a static electric field develops in the dielectric that stores energy and produces a mechanical force between the conductors. An ideal capacitor is characterized by a single constant value, capacitance, measured in farads. This is the ratio of the electric charge on each conductor to the potential difference between them.

Capacitors are widely used in electronic circuits for blocking direct current while allowing alternating current to pass, in filter networks, for smoothing the output of power supplies, in the resonant circuits that tune radios to particular frequencies and for many other purposes.

DIODE:

In electronics, a diode is a two-terminal electronic component that conducts electric current in only one direction. The most common function of a diode is to allow an electric current to pass in one direction (called the diode's forward direction) while blocking current in the opposite direction (the reverse direction). This unidirectional behavior is called rectification, and is used to convert alternating current to direct current, and to extract modulation from radio signals in radio receivers.

However, diodes can have more complicated behavior than this simple on-off action. This is due to their complex non-linear electrical characteristics, which can be tailored by varying the construction of their P-N junction. Today most diodes are made of silicon, but other semiconductors such as germanium are sometimes used.

TRANSORMER:

Here we using 12-0-12 step down transformer,which convert 220volt signal in to 12 volt.A transformer is a device that transfers electrical energy from one circuit to another through inductively coupled conductors—the transformer's coils. A varying current in the first or primary winding creates a varying magnetic flux in the transformer's core and thus a varying magnetic field through the secondary winding. This varying magnetic field induces a varying electromotive force (EMF) or "voltage" in the secondary winding. This effect is called mutual induction.

If a load is connected to the secondary, an electric current will flow in the secondary winding and electrical energy will be transferred from the primary circuit through the transformer to the load. In an ideal transformer, the induced voltage in the secondary winding (Vs) is in proportion to the primary voltage (Vp), and is given by the ratio of the number of turns in the secondary (Ns) to the number of turns in the primary (Np) as follows:

By appropriate selection of the ratio of turns, a transformer thus allows an alternating current (AC) voltage to be "stepped up" by making Ns greater than k, or "stepped down" by making Ns less than Np.

BASIC TRANSFORMAR STRUCTURE

Power supply:

WORKING

The power supply is used to give required voltage to the circuit. The power supply used here is of 12 volt dc. First the AC voltage is fed into a step-down transformer. This is used to step-down the AC voltage to into approx 12 volt. Then this voltage is fed into a rectifier which converts the AC voltage into DC supply. A capacitor is used in the circuit to rectify the ripples of rectified DC.

The capacitor is used parallel in the circuit. Then a voltage regulator IC 7805 is used to convert this HIGH DC supply into the LOW DC supply of 5volt.

Then at the last there is coupling capacitor connecting parallel in the circuit. This is used to couple the circuit to the load.

BIBLIOGRAPHY

www.google.com

www.wikipedia.org

www.electronicsforu.com

book: electronicsforyou