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What area unit the variations between BJT and MOSFET?

The Transistors BJT & MOSFET area unit electronic semiconductor devices that provide a giant ever-changing electrical o/p signal little|for little|for tiny} variations in small i/p signals. because of this feature, these transistors area unit used as either a switch or AN electronic equipment. the primary semiconductor unit was free within the year 1950 and it is treated united of the foremost essential inventions within the twentieth century. it’s quickly developing a device and additionally, varied types of transistors are introduced. the primary form of {transistor|junction semiconductor unit|electronic transistor|semiconductor device|semiconductor unit|semiconductor} is BJT (Bipolar Junction Transistor) and MOSFET (Metal compound Semiconductor Field impact Transistor) is another form of transistor introduced later. For a higher understanding of this idea, here this text offers the most distinction between BJT and MOSFET.

What is BJT?

A bipolar semiconductor could be a one form of conductor and within the past days these devices area unit utilized in the place of vacuum tubes. The BJT could be a current-controlled device wherever the o/p of the bottom terminal or electrode terminal could be a perform of this within the base terminal. essentially, the operation of a BJT semiconductor unit is set by this at the bottom terminal. This semiconductor unit carries with it 3 terminals specifically the electrode, base and collector. Actually, a BJT could be a semiconducting material piece includes 3 regions and 2 junctions. the 2 regions area unit named the P-junction and N-junction.


There square measure 2 forms of transistors specifically PNP and NPN. the most distinction between BJT and MOSFET square measure their charge carriers. In PNP semiconductor, P stands for positive and therefore the majority charge carriers square measure holes whereas in NPN semiconductor, N stands for negative and therefore the majority charge carriers square measure electrons. The operative principles of those transistors square measure much equal and therefore the main distinction is in biasing still because the polarity of the ability offer for every kind. BJTs square measure apt for low current applications like change functions.

Working Principle of BJT

The regulation of a BJT concerned within the use of Voltage between the 2 terminals like base and electrode to manage the flow of current through collector terminal. as an example, the configuration of a typical electrode is shown within the figure below.


The amendment in voltage affects the present getting into in Base terminal and this current can successively impact the o/p current referred to as. By this it’s shown that the input current controls the flow of o/p current. therefore this electronic transistor could be a current controlled device. Please follow the below link to grasp additional about; the foremost distinction between BJT and junction transistor.

What is MOSFET

The MOSFET could be a one quite junction transistor (Field impact Transistor), that consists of 3 terminals particularly gate, supply and drain. Here, the drain current is controlled by the voltage of gate terminal thus, these transistors square measure voltage controlled devices.

These transistors area unit obtainable in four different kinds like P-channel or N-channel with either in improvement mode or depletion mode. The supply and Drain terminals area unit fabricated from semiconductor device for N-channel MOSFETs and equally for P-channel devices. The gate terminal is created of metal and detached from supply & drain terminals employing a metal chemical compound. This insulation roots low power consumption a profit during this junction transistor. Therefore, this junction transistor is employed wherever p and n channel MOSFETs area unit used as building blocks to scale back the ability consumption like digital CMOS logic.

MOSFETs area unit classified into 2 varieties like improvement mode and depletion mode

 Depletion Mode: once the voltage on the ‘G’-terminal is low, then the channel shows its GHB electrical phenomenon. because the voltage on the ‘G’-terminal is positive or negative, then channel conduction is attenuate.

 Enhancement Mode: once the voltage on the ‘G’-terminal is low, then the device doesn’t conduct. once the additional voltage is applied to the gate terminal, then the conduction of this device is sweet.

 Please follow the below link to understand additional about; what’s MOSFET with Working?

Working Principle of MOSFET

The operating of MOSFET depends upon the MOS (metal chemical compound capacitor) that is that the essential a part of the MOSFET. The chemical compound layer presents, among the 2 terminals like supply and drain. By applying +Ve or –Ve gate voltages, we will set from p-type to n-type. once a +Ve voltage is applied to the gate terminal, then the holes existing below the chemical compound layer with a repulsion and holes area unit pushed down through the substrate. The deflection region occupied by the sure –Ve charges that area unit related to the acceptor atoms.

Difference between BJT and MOSFET

The main distinction between BJT and MOSFET transistors square measure mentioned below.

  • The BJT may be a bipolar semiconductor device|transistor|electronic transistor|semiconductor device semiconductor unit semiconductor} whereas MOSFET may be a metal compound semiconductor field result transistor.
  • A BJT has 3 terminals particularly base, electrode and collector, whereas a MOSFET has 3 terminals particularly supply, drain AND circuit.
  • BJT’s square measure used for low current applications, whereas MOSFET is employed for prime power applications.
  • Nowadays, in analog and digital circuits, MOSFETs square measure treated to be a lot of unremarkably used than BJTS.
  • The operating of BJT depends on this at the bottom terminal and therefore the operating of the MOSFET depends on the voltage at the compound insulated gate conductor.
  • The BJT may be a current controlled device and MOSFET may be a voltage controlled device.
  • MOSFETs square measure used quite BJTs in most of the applications
  • The structure of the MOSFET is a lot of advanced than BJT

Thus, this can be all concerning the distinction between BJT and MOSFET which incorporates what square measure BJT and MOSFET, operating principles, kinds of MOSFET, and variations.We hope that you just have gotten an improved understanding of this idea. what is more, any doubts concerning this idea or electrical and electronic comes, please offer your feedback by commenting within the comment section below. Here may be a question for you, what square measure the BJT and MOSFET characteristics?

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