Bipolar Junction Transistor and Its Benefits

The transistor is a semiconductor device, which can amplify the electronic signals, such as radio and television signal. It is an important ingredient of every electronic circuit. 

Transistor is a three terminal device, such as Base, Emitter, and Collector. It can be operating by three configurations, such as common base, common emitter, and common collector. According to the configuration mode it can be use for voltage as well as current amplification. The concept of transfer of resistance has given by the name of transfer resistor.

There are two types of transistors, such as unipolar junction transistor and bipolar junction transistor. In uni-polar transistor the current conduction is only due to one type of carriers, as majority carriers. The current conduction in bipolar transistor is because of both the types of charge carriers are holes and electrons. Therefore this is called bipolar junction transistor.

The bipolar junction transistor has two types, 

1. N-p-n type
2. P-n-p type

Principle of Bias Transistor:

To operate the transistor properly as an amplifier, it is necessary to bias correctly the two p-n junctions with external voltages. Depending upon the external bias voltage polarity usage and the transistor works in one three regions. 

1. Active region
2. Cut-off region
3. Saturation region

Construction of a transistor: 

The transistor can be constructing by use of the five basic techniques and accordingly they are classified as,
1. Grown type
2. Alloy type
3. Electro chemically etched type
4. Diffusion type

Grown Type: 

This technique is used to form the two p-n junctions of a grown-junction transistor. A single crystal is drawn from a melt of silicon or germanium whose impurity concentration is change during the crystal drawing operation.

Alloy Type: 

This type of construction is p-n-p transistor. Such construction is also known as fused construction. Here the center section is a thin wafer of n-type material. The collector is made larger than the emitter to withstand the heavy current and power dissipation at the collector base junction.

Electronically Etched Type:

In this technique, etching depression is made on opposite sides of the semiconductor wafer to reduce the thickness of the base region. The electro-chemically etching devices are also referring to the surface-barrier transistor. However these devices are no longer of commercial importance.

Diffusion Type:

Diffusion is a process, by which a heavy concentration of particles will diffuse into the surrounding region of lesser concentration. The primary difference between the diffusion and the alloy process is the fact that liquefaction is not reach in the diffusion process. Heat is applied to the diffusion process only to increase the activity of the elements can be involved.

Transistors & Their Importance

A transistor is a small electronic device that can cause changes in a large electrical output signal by small changes in a small input signal. That is, a weak input signal can be amplified by a transistor. A transistor consists of three layers of silicon or germanium semiconductor material. Impurities are added to each layer to create a specific electrical positive or negative charged behavior. "P" is for a positive charged layer and "N" is for a negative charged layer. Transistors are both NPN or PNP in the configuration of the layers. There is no main difference except the polarity of voltages that need to be applied to make the transistor operate.

The transistor is the building block for modern electronic devices and preceded radios, calculators, computers, and other modern electronic systems. Inventors were actually awarded the Nobel Prize in 1956 for inventing the transistor. It can be argued that it is one of the most important inventions of the 20th century. In 2009, the first transistor invented by Bell Labs was named an IEEE Milestone. There are over a billion individual transistors that are produced each year (known as discrete transistors).

However, a large majority are produced in integrated circuits along with diodes, resistors, capacitors, and other electronic components, comprising electronic circuits. Transistors can be used in a quantity of anywhere from 20 in logic gates to 3 billion in a microprocessor. Because of the low cost, flexibility, and reliability associated with the transistor, it has become extremely widely produced. To put things into perspective, there were 60 million transistors built for every person on Earth back in 2002. Now over two decades later, that number only continues to grow.

The two types of transistors are the bipolar transistor and the field-effect transistor, which have slight variations in terms of how they are utilized in a circuit. Transistors are usually used as electronic switches for both high-power and low-power applications. They can also be used as amplifiers in that a small change in voltage changes the small current through the base of the transistor. Some key advantages of transistors over other products are small size, minimal weight, no power consumption by a cathode heater, a warm-up period for cathode heaters required after power application, higher reliability, greater physical ruggedness, extremely long life, and insensitivity to mechanical shock and vibration, between others.

Top manufacturers for transistors are Maxim Integrated, Micro semi Power Products Group, Amsyx, ON Semiconductor, Panasonic Electronic Components and Toshiba.

If you Google for best transistor components you will get many one stop shops for any transistor parts you are looking for, regardless of who manufactures it or what the purpose is.