THE DESIGN AND CONSTRUCTION OF A 40 WATT HI-FI AMPLIFIER

THE DESIGN AND CONSTRUCTION OF A 40 WATT HI-FI AMPLIFIER

CHAPTER ONE

INTRODUCTION

High power amplifier are usually quite costly and usually beyond the easy reach of most audio enthusiastic (and Hi-Fi buffs) who then have to remain satisfied with those small 6 watt amplifiers. Well, with this introduction to us and to electronics, things should change. Well this low cost Hi-Fi amplifier that delivers ear chatting and thundering output of an unbelievable forty watts. The unique features of this circuit are.

vLow cost – The basic criteria

vCompact size

vVery low transient noise on “power on” and low THO

vEffective Bass and treble controls

vAutomatic thermal shut down system it switches off the amplifier in case of overheating

vLoad damp protection in built.

The circuit uses a high power amplifier chip viz the LA 4440. the circuit is quite self explanatory. The input is coupled by a small value capacitor. The output is taken through a block terminal and fed to the speaker.

CHAPTER TWO

Most electrical electronics components are made up of mechanical and electrical contacts, electromagnetic coils, protecting devices, switches and indicating devices for circuit operation, for this reason adequate precaution is needed when selecting or determining the components and the following points as to be considered.

vRating of the equipment to be controlled

vRating of the components parts

vThe operation voltage and current

vTemperature co-efficient of the components

vMode of operation

vReliability of the components

The 40 watt Hi-Fi amplifier components are described and it operational method and control.

The components are:

vCapacitor resistor

vPrinted circuit board

vLoudspeaker

vCabinet screw

vHeat sink

vVariables (volume control)/ variable resistor

vIntegrated circuit (IC LA 4440)

vDiode

CAPACITOR

A capacitor stores electric charge. Basically it consists of two metal plates separated by an insulator called the dielectric. When connected to a battery the capacitor charges up until the potential different between it’s terminals is the same as the e.m.f of the battery, if the battery is removed, the charge may take a long time to leak away unless a conductor is connected across the terminals.