Transistors - special purpose refers to a category of transistors that are designed for specific applications or uses. These transistors are typically variations of the basic transistor designs, with some added features or characteristics that make them well-suited for a particular application. Some examples of special purpose transistors include:
Darlington transistors: These are transistors that consist of two transistors connected in such a way that the current amplified by the first transistor is amplified even further by the second transistor. This configuration allows Darlington transistors to have a much higher current gain than a single transistor, making them useful in applications where high current amplification is needed.
Phototransistors: These are transistors that are sensitive to light. They are commonly used in light-sensitive circuits, such as in burglar alarms or automatic streetlights.
FETs: Field-effect transistors (FETs) are a type of transistor that uses an electric field to control the flow of current. They are commonly used in digital circuits because they can be easily switched on and off to create the binary digits (1s and 0s) that are the basis of digital information.
RF transistors: RF transistors are transistors that are designed for use in radio frequency (RF) circuits. They are commonly used in RF amplifiers and RF mixers, where they can handle high-frequency signals and provide good linearity.