For information, a bipolar transistor is basically a current amplifier, and a MOSFET is basically a voltage controlled current amplifier. Both are used in completely different ways. MOSFET stands for Metal Oxide Semiconductor Field Effect Transistor. In Bipolar transistors, the current that flows between the collector and emitter is regulated by (and an amplification of), the current that flows from the base to the emitter. In a FET the voltage present at the gate determines the current that will flow between the drain and source.