Distinction between a BJT and FET:
BJT |
FET |
BJT is a bipolar device i.e. the conduction is because of two (bi) carriers - electrons and holes. |
FET is a Unipolar device i.e. the conduction is because of either electrons in case of n-channel FET or holes in case of p-channel FET. |
BJT is a Current controlled Device. This means that the output current is a function of the input current. |
FET is a Voltage Controlled Device. This means that the output current is a function of the input voltage |
There are two types: n-p-n and p-np BJT transistors |
These are two types: n-channel and p-channel FETs |
Comparatively low input impedance |
Very high input impedance |
Difficult to integrate on Integrated Chips |
Easy to integrate on Integrated Chips |