Question

what are the differences between BJT and FET?

Answer 1

BJT
bipolar junction transistor
FET
field effect transistor

BJT: Secondary break down occurs.
Lower Input impedance
Lower operating frequency
Higher switching losses

FET: PTC for resistance
No sec break down
Higher operating frequency
Higher input impedance
lower swithing losses

Source(s):
http://www.differencebetween.net/technology/difference-between-bjt-and-fet/

Answer 2

The term FET is a generic for many devices. This is Field Effect Transistors. There are JFET( junction field transistor), MOSFET( Metal Oxide semiconductor FET), MESFET and some more( you can find more these kind of devices on net).

1) BJT is a current controlled device. In this There are three current components emitter, base , collector \[Ic=Ie+Ib\]. On the other hand FET is a voltage controlled device. U apply voltage at one terminals( usually refereed as GATE terminal)

2) The input impedance of BJT is low. This is a current flow at input terminal of it. But FET is having High input impedance. In JFET the input is applied by reverse biasing the diode between gate and source terminal. In MOSFET this there is oxide between gate and source terminals .

3) BJT is a bipolar device. In this current constitute of both electron current and hole current . But in FET either it is electron current in (n-channel) and hole current is (p-channel fet)

Please refer to internet for more differences and their details

Answer 3

yes vkp answer is writ