Industrial PCsA field-effect transistor (FET) is a type of transistor that uses an electric field to control the flow of current between its input and output terminals. FETs are commonly classified as either bipolar or unipolar, depending on the type of current they conduct. Bipolar FETs, or BJTs, conduct both positive and negative charges, whereas unipolar FETs, such as metal-oxide-semiconductor FETs (MOSFETs), only conduct one type of charge. MOSFETs are the most common type of FET, and are used in a wide range of electronic circuits and systems. Single FETs are individual FETs that are not part of a larger integrated circuit (IC) or package. They are commonly used in prototyping and other applications where a small number of FETs are needed.