CHAPTER ONE
1.0 INTRODUCTION
DESCRIPTION/FUNCTIONS OF THE COMPONENTS USED IN THE PROJECT
1. POWERS SUPPLY/TRANSFORMER
The power supply is culmed produce power required by the component to function. It coverts line voltage which is AC to DC and to a level that can be used by the various components. This is achieved by the use of a step down transformer to step down rectify, filtrate and regulate the line voltage.
CIRCUIT SYMBOL
THE SHIFT REGISTER
The shift register is a serial-in, parallel out register, it is responsible for the display “WELCOME TO ELECT/ELECT DEPT.” WELCOME” comes up frist, after some time interval which will be determined by the 1MSO resistor or a variable resistor “TO” come up, followed by “ELECT/ELECT” and finally “DEPT”.
The process is repeated, The counter is a decade counter with a decorded outputs. It controls the boarder display pattern in the form of light laser pattern.
The rate at which the lights display is determined by the frequency of the 55C1MOS timer chip which acts as a clock generator that generates square wave to the counter.
Hence, the timing of the whole circuit is controlled by the four 555CMOS I.C. in the circuit. Each timer controls the sequence of each lamp at the terminal with the help of the relay drive.
CIRCUIT SYMBOL
RELAY
A simple relay is made from a coil of wire wound around a soft iron core with the ends of this coil at erminals, when it is energized the soft iron core become a magnet and attracts the armature.
The working principle of simple normally open relay found a wide application in this circuit for the switching “ON” and “OFF” of the lamps.