Question

main difference between transistor and FET

Answer 1

Transistors are three terminal devices, in the days of tubes they were called triodes. There's three basic semiconductor types, Bipolar Junction Transistors, BJT, Field Effect Transistors, FET, Medal Oxide Transistors, MOSFET. The mechanism of operation are slightly different for each as well as the DC and Signal models.

Answer 2

a transistor is a bipolar device which is current controlled device( da base current) where as FET is a unipolar device and voltage controlled device

Answer 3

FET is a one type of transistor ...field effect transistor....that works with the effect of magnetic field of current