Difference between BJT and MOSFET

BJT and MOSFET both transistors are useful for amplification and switching applications. Yet, they have many similarities and also different characteristics. As a result, one or the other may be better suited to specific electronics applications. 
  • A BJT has a negative temperature coefficient device, so current sharing resistors are necessary during parallel operation of BJT's while in MOSFET has a positive temperature coefficient for resistance makes the parallel operation of MOSFET is easy.
  • BJT, with a decrease in resistance at that time rise in temperature, the current increases. This increased current over the same area results in hot spot and breakdown of the BJT because of negative temperature coefficient occurs, the secondary breakdown does occur, Whereas in MOSFET device secondary breakdown does not occur, because it has a positive temperature coefficient. 
  • BJT stands for bipolar junction transistor, and MOSFET stands for metal oxide semiconductor field effect transistor.
  • BJT is a bipolar device, MOSFET is a uni-polar power electronics device.
  • A BJT has three terminal called an emitter, base and collector, whereas a MOSFET  also has a three-terminal called gate, source and drain. 
  • BJT current controlled device while MOSFET is a voltage controlled device.   
  • BJT's are used for low current applications, while MOSFETs are used for high power applications.      
  • BJT has a low input impedance (a few kilo-ohms), a MOSFET has a high input impedance  (megaohm).  
  • In the analogue and digital circuit, MOSFET is considered to be more commonly used compare to  BJT now these days. 
  • MOSFET's in higher voltage ratings have much more conduction loss.
  • BJTs are available with ratings up to 1200 V and  800 A, and MOSFETs are available with ratings upon 500 V and 140 A. 
  • BJT depends on the current at the base terminal and the MOSFET depends on the voltage at the oxide-insulated gate electrode. 
  • MOSFET structure is more complex than BJT.