Transistor as switch: A transistor is a device that regulates current or voltage flow and acts as a switch or gate for electronic signals. Transistors consist of three layers of semiconductor material, each capable of carrying a current. The transistor was invented by three scientists at the Bell Laboratories in 1947. A transistor consists of three layers of semiconductor material, each capable of carrying a current.
The main purpose of Transistor
A transistor is an electronic device containing three layers of silicon. The behavior of electric charges in the silicon lets the transistor act as a valve, controlling the flow of electricity through it.
Transistor is amplifier
As with its ancestor the vacuum tube, the transistor can control a large electric current with a weak one. This is used to boost the power of audio, radio, television, and other signals.
Transistor as switch
Transistors can b used as transistor switch signals on and off at high speeds. They form the basis for modern computers, which run at billions of operations per second.
Phototransistors control electrical signals by sensing light. Communications systems use them to handle data sent by the laser beam.
Organic light-emitting devices (OLEDs) are transistors that give off light. As with liquid-crystal displays (LCDs), you can make flat display screens with them.
Different Types of Transistors
There are varieties and different types of transistors available in today’s market including Bipolar, Darlington, IGBT, and MOS FET Transistors.
Bipolar Transistor – A Bipolar Junction Transistor (BJT) is a three-terminal electronic device made of doped semiconductor material and may be used in amplifying or switching applications. Bipolar transistors are so named because their operation involves both electrons and holes. A bipolar transistor will have terminals that are labeled: emitter, collector, base. A small current at the base terminal (passing from the base to the emitter) can modify or switch a much larger current between the collector and emitter terminals.
Darlington Transistor – The Darlington Transistor is actually two bipolar transistors, connected in such a way that the current amplified by the first transistor is amplified even further by the second one. This model offers a higher common-emitter current gain than if both types of transistors are separated and can even take up less space because both transistors can share a collector.
IGBT Transistor – An Insulated Gate Bipolar Transistor (IGBT) is a three-terminal power semiconductor device typically used as an electronic switch. IGBT’s are types of transistors that are capable of switching electric power in many modern appliances such as electric cars, trains, variable speed refrigerators, air-conditioners and even stereo systems with switching amplifiers.
MOSFET Transistor – A Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET) is used in integrated circuits to control the conductivity of a channel. MOSFETs are highly dependent on negative and positive charges. They have many purposes, including limiting a device’s power levels, storing data, and is used as a switch for a wide variety of electronic devices.
A light description of Transistors has been given above if you want to know more detail please read the properties of transistors in detail.