Why j fet called voltage control device?

A Junction Field-Effect Transistor (JFET) is called a voltage-controlled device because its operation is governed by the voltage applied to the gate terminal. This gate voltage creates an electric field that modulates the conductivity of the channel, allowing or restricting the flow of current between the source and drain terminals. Consequently, small changes in gate voltage can lead to significant changes in current, making it a key component in amplifying and switching applications.