Mumbai University > Electronics ana telecommunication engineering > Sem 3 > Analog electronics 1

Marks: 5M

Years: May 15

FE'T is a voltage controlled device, i.e. voltage at the input terminal controls the output current, and whereas BJT is a current controlled device i.e. the input current controls the output current.

FET: Voltage Controlled Device

As shown in the Fig. 2.6, in BJT the output current, I_C is controlled by the base current $I_B$. Hence BJT is a current controlled device. On the other hand, in FET, the voltage applied between gate and source $V_GS$ controls the drain currentI_D.

Therefore, FET is a voltage controlled device. The name "field effect" is derived from the fact that the output current flow is controlled by an electric field set up in the device by an externally applied voltage between gate and source terminals.