What is the major difference between a bipolar and unipolar device?
As their name implies, Bipolar Transistors are “Bipolar” devices because they operate with both types of charge carriers, Holes and Electrons. The Field Effect Transistor on the other hand is a “Unipolar” device that depends only on the conduction of electrons (N-channel) or holes (P-channel).
What is the symbol of BJT?
The basic symbols of BJT are n-type and p-type. Electronic current is conducted by both free electrons and holes in bipolar junction transistor.
Why bipolar junction transistor is called bipolar?
device is often called the bipolar junction transistor because its operation requires that the negatively charged electrons and their positively charged counterparts (the holes corresponding to an absence of electrons in the crystal lattice) coexist briefly in the presence of one another.
What is common base configuration?
In common base configuration, emitter is the input terminal, collector is the output terminal and base terminal is connected as a common terminal for both input and output. Thus the base terminal of a transistor is common for both input and output terminals and hence it is named as common base configuration.
What is a bipolar device?
Bipolar transistors are a type of transistor composed of pn junctions, which are also called bipolar junction transistors (BJTs). Whereas a field-effect transistor is a unipolar device, a bipolar transistor is so named because its operation involves two kinds of charge carriers, holes and electrons.
What is alpha and beta in BJT?
Alpha of a transistor is the current gain in common base configuration defined as the ratio of change in collector current to change in emitter current while beta is the current gain in CE configuration. It is defined as the change in collector current to base current.
Why Ujt is called Unijunction?
A Unijunction Transistor (UJT) is a three terminal semiconductor switching device. Since there is only one rectifying junction within the device, it is called a ‘Unijunction’ transistor.
What are the three elements of bipolar transistor?
A BJT consists of three differently doped semiconductor regions: the emitter region, the base region and the collector region.
Where is common-base used?
It is mainly used at high frequencies where low source resistance is common. It is used for impedance matching in circuits with very low output resistances to those with a high input resistance.
Why is common-base used?
Due to its input-output impedance characteristics, the common base amplifier arrangement is extremely useful in audio and radio frequency applications as a current buffer to match a low-impedance source to a high-impedance load or as a single stage amplifier as part of a cascoded or multi-stage configuration where one …