When in cutoff mode, a transistor functions like an open electrical switch. This is the most common use of transistors and they can be found in a variety of electronic circuits. In active mode, transistors are used to amplify signals. Operating Modes of Transistors Active Mode

However, due to their construction, FET transistors have a much higher input impedance than BJT transistors which makes them less suitable for use in analog applications where high gain is required. FETs are commonly used as switches in digital circuits because they can be controlled by voltage or current sources and require very little current to operate. They are relatively easy to control and require less power for switching than BJT transistors. On the other hand, FETs have four terminals – Gate, Source, Drain and Body. This type of transistor works well for low power applications but requires more voltage for switching than a FET. Acting like an electrical switch, a current passing through the base terminal enables electrons to flow between collector and emitter terminals. īefore we can identify the most suitable method of using a transistor as a switch, we must first gain insight into the two predominant types of transistors employed for this purpose: BJT (Bipolar Junction Transistor) and FET (Field Effect Transistor).Ī BJT consists of three terminals – Collector, Base and Emitter. In addition, they are also commonly found in amplifiers, power supplies and other audio equipment. Transistors are widely used in computing applications such as memory storage, logic gates and integrated circuits.

By controlling the amount of electric current that flows through a circuit, transistors can be used to amplify or reduce signals in electrical circuits. It acts as a switch, allowing electric current to flow through the circuit when the switch is on and blocking it when the switch is off. A transistor is an electronic device consisting of three terminals, which are used to control electric current and voltage within a circuit.

Transistor saturation mode