Why BJT is bipolar and MOSFET is unipolar?
BJT is called bipolar because the current in a BJT flows due to both electron and hole carriers, whereas the current in a Field Effect Transistor (FET) flows due to either electron carriers for N-type FET or hole carriers for P-type FET, hence they’re called unipolar transistors.
What is the significance of the arrow head in the transistor symbol?
The arrow indicates the direction of flow of holes i.e. the direction of conventional current, opposite to the flow of electrons in a transistor.
Is MOSFET unipolar?
Thus, the MOSFET, like the FET is a unipolar device. One type of charge carrier is responsible for conduction.
What are the two major differences between a mechanical switch and a transistor?
Another difference – A normal switch has only two positions although it may produce electrical bounce when switching from one state to the other. A transistor is perfectly capable of being at any position in between the two endpoint states, ie. it can function as something other than a switch.
Which of the transistor current is always the largest?
emitter current IE
The emitter current IE is always the largest one. The base current IB is always the smallest. The collector current IC and emitter current IE are relatively close in magnitude.
What’s the difference between BJT and MOSFET transistors?
Key Differences between BJT and MOSFET. The key differences between BJT and MOSFET transistors are discussed below. The BJT is a bipolar junction transistor whereas MOSFET is a metal oxide semiconductor field-effect transistor.
Which is the PN junction in JFETs and BJTs?
In BJTs the PN junction is the base-emitter one. In JFETs it is the one between gate and channel. In MOSFETs it is the one which exists between the channel and the substrate (the terminal where the arrow is placed in the symbols you posted), which is not available externally.
How many terminals does a bipolar junction transistor have?
A Bipolar Junction Transistor (BJT) is a current-controlled semiconductor device which has three-terminals. The current in BJT is carried by both majority and minority carriers so it is known as bipolar device.
How is the base-emitter junction biased in a BJT?
The base-emitter junction is forward biased by the dc source V EB and the collector-base junction is reverse biased by the V CB. So the depletion layer width at E-B junction is reduced and depletion layer width at the C-B junction is increased. 1.