CHAPTER ONE
INTRODUCTION
All modern engineering system includes certain aspects of control system at some point in their broadcast scenes, control engineering and the associated theory are concerned with the means of making system to behave in a desired may.
The system on this thesis is a DC " AC inverter which is an apparatus used in the conversion of direct current (DC) to alternating current (AC).
In our contry today, this equipment is not all that in use not because it is not important but because people never give it a thought as per the construction and design.
It is meant for use with a 12volts leadacid battery of it’s in a car for example a suitable output voltage of 240volts AC  obtainable.
This output voltage of 240volts AC can be used for powering small electrical appliances such as lights, electrical tools radio, soldering iron, fan etc. However,  it is with mentioning that the DC generated with this appliance is nothing comparable to the AC generated by big generation duration. This appliance is therefore suitable for short time replacement for the real AC generation especially in the remote areas and it is install where electrical appliances are sold and the need might arise for it to be tested and certified good.
Another main area where this equipment can be of great utility is in communication system. In a situation where there is a constant AC power supply failure example in offices DC " AC inverter is needed and such cases, inverter can be used as a source of light.
Most industries in the country do not make use of DC " AC inverter because the are through to be costly with respect to the task they perform. However, putting into consideration the task, this appliance can perform. It can be concluded that it is cheaper. The construction is simple, cheaper, easy to operate and portable. The usefulness of this device and the function cannot be over emphasized especially now that our country is passage through a very sensitive era in our power generating Authority (NEPA) has been dubbed NEVER EXPECT POWER ALWAYS. In these times when control and monitor of complex field operations have based in computer, a failure of AC, power supply to communication equipment means work stoppage and to some small scale industries a lot of economic and materials losses is avoidable.