ABSTRACT
The main aim of this project is to construct an inverter. Inverters have many applications especially in modern electronic devices such as computers. The inverter is designed to convert D.C from 12volt battery to 120volt A/C, the D.C supply is fed to an astable multivibrator which produces a square waveform. These pulses serve as the input of a stepup transformer to give an output of 120volt.

CHAPTER ONE
1.0INTRODUCTION
The most recent advancement in technology has really given birth to different development in the field of engineering. Provision has been made by technologist who covers a wide range of humans environment, given solution to humans problems.
In the recent times, power supply has been epileptic in the country which has really affected consistent power source. Many power systems were found to be able to maintain power supply to the load during mains failure PHCN. Most of these loads were designed so that electrical supply to them should be maintained without interruption. Electricity can be generated by devices to convert some readily available sources of energy since electricity generation can be interrupted at any time as a result of fault and all electronic devices need an alternating current , the use of an inverter to utilize an alternative source of energy becomes so necessary.
An inverter is an electronic device which converts DC energy to AC energy. Thus, the technological breakthrough resulting to the production of this system has encouraged the optimum utilization of computers and related equipments. The beauty of inverter system is the fact that it accepts all the power anomalies, conditions and filters properly the public power supply output to most load which require pure grade sinusoidal voltage rated output. They are used in a wide variety of applications such as the complicated electronic systems of orbiting satellite and cool astronaut suites. Inverters are also used to operate gyroscope and other air borne instruments. Due to low voltage power sources such as solar cells, nuclear cells, and fuel cells, inverters has become increased in demand.
The system is unaffected by variation in the mains supply and during the period of power failure will continue to supply to the load for a specified duration. Modern DC to AC inverters is reliable and requires less maintenance

1.1AIMS AND OBJECTIVES
The purpose of this project is aimed at designing and constructing a DC/AC inverter. It is necessitated by the quest to supply voltage to electrical electronic appliances in the advent of power failure from the mains PHCN.

1.2JUSTIFICATON
In this design, the DC/AC inverter should be able to switch over to an alternating current AC at the advent of been powered by the mains and automatically charging the battery and reverse is the case when there is power failure from the mains.

1.3LIMITATION
The DC/AC inverter can be produced or designed in different wattage as well as the output voltage models depending on the wattage and output voltage required by the users. It can be mounted or used in different areas of interest e.g. computer systems, ATM, household electronics either 120v or 240v output or many more.

1.4METHOLOGY
A modular approach was adopted in which the design was incorporated namely, DC/AC converter unit The astable multivibrator low/high voltage transformation unit, charging unit, output unit.
These subunits would be designed, constructed and tested separately when all are confirmed to be working properly, there shall be appropriately connected. As much as practicable integrated circuit IC chips will be used to reduce components carried and enhance compatibility and reliability of the systems.