Transistor

Let Us Learn About Transistor

A transistor is a semiconductor, differentiated from a vacuum tube primarily by its use of a solid, non-moving part to pass a charge. Transistors are crucial components in virtually every piece of modern electronics, and are considered by many to be the most important invention of the modern age



The VEE supply is used to forward bias emitter base junction. As a result significant current flows, once the potential barrier is exceeded. The majority charge carriers diffuse from emitter into base and this result in emitter current IE as indicated in the above diagram. Once these reach the base, very few electrons or hole undergo recombination process and rest diffuse through collector base junction due to potential on the collector side. In a PNP the diffused holes reach the collector and at the same time an electron from the emitter enters into the positive pole of VEE thereby creating a hole in the emitter. Thus the current in PNP is caused by holes and the current in external circuit by electrons.
Due to very less recombination process, the IC - IE. Apply Kirchhoffs current law.
IE = IB + IC

The action of NPN is similar to that of PNP.

Transistor circuit configuration
The three types of circuit connections for operating a transistor:

i) Common base (CB) configuration
ii) Common emitter (CE) configuration
iii) Common collector (CC) configuration
The common electrode is generally grounded and is common to the input and output circuit.

Benefits of Transistors

Compared to the vacuum tubes that were used previously, the transistor was an amazing advance. Smaller in size, the transistor could easily be manufactured cheaply in large quantities. They had various operational advantages, as well, which are too numerous to mention here.

Some consider the transistor to be the greatest single invention of the 20th century, since it opened so much in the way of other electronic advancements. Virtually every modern electronic device has a transistor as one of its primary active components. The computer, in all of its modern forms, could not exist without transistors.

Other Types of Transistors

There are a wide variety of transistor types that have been developed since 1948, and a description of all of them would require more space and technical expertise than is I have. Here's a list (not necessarily exhaustive) of various types of transistors:

• Bipolar junction transistor (BJT)
• Field-effect transistor (FET)
• Heterojunction bipolar transistor
• Unijunction transistor
• Dual-gate FET
• Avalanche transistor
• Thin-film transistor
• Darlington transistor
• Ballistic transistor
• FinFET
• Floating gate transistor
• Inverted-T effect transistor
• Spin transistor
• Photo transistor
• Insulated gate bipolar transistor
• Single-electron transistor
• Nanofluidic transistor
• Trigate transistor (Intel prototype)
• Ion-sensitive FET
• Fast-reverse epitaxal diode FET (FREDFET)
• Electrolyte-Oxide-Semiconductor FET (EOSFET)