CHAPTER ONE
1.0 INTRODUCTION
The era of solid state electronics began with the invention of transistor in (1947) at Bell Laboratory. Then the Inventors were Walter Britain, John Bardeen and William Shockley. The transistors were produced commercially in 1951. The companies like RCA Raytheson General Elutic Westinghouse and Westen Electic were the first to fabricate transistors.
In 1958, it was thought that germanium and silicon can be used to build an entire circuit, called Monolitic Circuit. Resistors were formed with the bult semi-conductor or by diffusing one semi-conductor into another. The capacitors were formed by using a metallic layer and the semi-conductor for the plate and oxide layer for the dielectric. In 1959, Noyce gave an idea for making multiple devices on a single piece of silicon, in order to make an inter-connection between devices as part of the manufacturing process. It could reduce.
The monolithic circuit was name an Integrated Circuit (IC). The IC’s were produced, commercially in 1961 by Fairchild and Texas Instrument.
1.1 BACKGROUND OF THE STUDY
When a third doped element is added to a crystal diode in such a way that two pn junctions are formed, the resulting device is known as a transistor.
The transistor- an entirely new type of electronic device – is capable of achieving amplification of weak signals in a fashion comparable and often superior to that realized by vacuum tubes. Transistors are far smaller than vacuum tubes, have no filament and hence need no weaking power and may be operated in any position.
They are mechanically strong, have practically unlimited life and can do some jobs better than vacuum tubes.
1.2 STATEMENT OF PROBLEM
The research was associated with problems which lead to the delay and valuability of the research work, one of the is to determine the characteristics of the bipolar transistor in circuit configurations which is very different and produces different circuit characteristics with regards to input impedance, output impedance and gain whether this is voltage gain, current gain or power gain. Other problems associated were time factor and financial constraints.
1.3 AIM/OBJECTIVES OF THE STUDY
The factors that gave rise to the determination of the I-V characteristics of a bipolar junction transistor in common base configuration are highlighted under the aims/ objectives below:
1.3.1 AIM
To study (simulate) the IV characteristics of a bipolar junction transistor in common base configuration.
1.3.2 OBJECTIVES
The objectives of the study upon completion of this work:
1. Low input resistance of about 100Ω will be achieved.
2. Very high output resistance of about 450kΩ will be achieved.
3. Voltage gain of about 150Ω and current gain of less than 1.
1.4 SIGNIFICANCE OF THE STUDY
Common base configuration is used for high frequency applications.
Also, the change in Rin with change in VBE gives rise to distortion of signals handled by the transistor. This characteristic is hardly affected by changes either in VCB or temperature.
1.5 SCOPE OF THE STUDY
The scope of this study is to construct a bipolar NPN transistor are shown above. The voltage between the Base and Emitter ( VBE ), is positive at the Base and negative at the Emitter because for an NPN transistor, in which the Base terminal is positive with respect to the Emitter.
1.6 LIMITATION OF THE STUDY
Common base configuration cannot be used for impedance matching and audio frequency applications because of its variation in Rin with change in base emitter voltage (VBE).
