A transistor is a fundamental semiconductor device used to amplify or switch electronic signals. There are several types: BJT (Bipolar Junction Transistor) operates using both electrons and holes and is current-controlled. JFET (Junction Field Effect Transistor) is voltage-controlled and uses a reverse-biased gate to control current flow. MOSFET (Metal-Oxide-Semiconductor FET), widely used in digital and power electronics, offers high input impedance and fast switching. IGBT (Insulated Gate Bipo