BJT and FET are electronic devices. The basic difference between BJT and FET is that the bipolar junction transistor is the bipolar and current control device, while FET (field effect transistor) is the unijunction transistor. It is a voltage control device.
The Difference between bjt and fet
|1:BJT (bipolar junction transistor ) is the bipolar device.||1:FET (field-effect transistor) is a unijunction transistor.|
|2:Its operation depends on both majority charge carriers and minority charge carriers.||2:Its operation depends on majority charge carriers which may be holes or electrons.|
|3:Input impedance of BJT is very less i.e (1k -3k)||3:Input impedance of FET is very large.|
|4:It is the current control device.||4:It is the voltage-controlled device.|
|5:It is noisier.||5:It is less noisy.|
|6:Its frequency variations affect their performance.||6:It has a high-frequency response.|
|7:It is a temperature-dependent device.||7:It has better heat stability.|
|8:It is cheaper.||8:It is costly than bjt.|
|9:It is bigger in size than FET.||9:It is smaller in size than BJT.|
|10:It has an offset voltage.||10:It has no offset voltage.|
|11:It has more gain.||11:It has less gain.|
|12:It has high output impedance because of high gain.||12:It has low output impedance because of less gain.|
|13:Its collector and base are more positive than the emitter.||13:Its Drain is positive, the gate is negative w.r.t to the source.|
|14:Its base is negative w.r.t to the emitter.||14:Its gate is more negative w.r.t to the source.|
|15:Bjt has three parts ( base, Emitter, and Collector).||15:Fet has three parts (Drain, Source, and Gate).|
|16:It has high voltage gain.||16:It has low voltage gain.|
|17:It has low current gain.||17:It has a high current gain.|
|18:Its switching time is medium.||18:Its switching time is fast.|
|19:It is easily biased.||19:Its biasing is difficult.|
|20:These are preferred for low current applications.||20:These are preferred for low voltage applications.|
|21:It requires a small amount of current to keep on.||21:They requires a small amount of voltage to keep on.|
|22:It consumes more power.
23:It has a negative temperature coefficient.
|22:It consumes less power.
23:It has a positive temperature coefficient.