A Darlington tube is two triodes connected together, and the polarity is only determined by the front triode. A Darlington transistor (also known as a Darlington pair) is a device that combines two bipolar transistors. In this way, the second transistor can further amplify the current amplified by the first transistor, saving space and obtaining a high gain (β or hFE). There are already products on the market in the form of integrated circuits, but Darlington pairs consisting of two separate transistors are still common. The historical Darlington pair was invented by Sydney and Darlington of Bell Labs. His patent covered a circuit with two to three transistors in a single chip, rather than an arbitrary number of transistors, because this would cover all Modern integrated circuit design. Related circuits A similar design that adds complementary transistors (including a pair of NPN and PNP transistors) is called a Sziklai pair, also known as a complementary Darlington pair of transistors.
The principle of Darlington tube
The Darlington tube is a composite triode. Two triodes are connected in series. The emitter of the first tube is connected to the base of the second tube. , so the amplification factor of the Darlington tube is the product of the amplification factors of the two triodes. Therefore, it is characterized by a very high amplification factor. The role of the Darlington tube is generally to amplify very small signals in highly sensitive amplification circuits. Such as high-power switching circuit. In electronic circuit design, Darlington connection is often used in power amplifiers and regulated power supplies.
Composition principles of Darlington tube composite tubes
Under the correct external voltage, each transistor works in the amplification zone.
The collector current or emitter current of the first element is the base current of the second element, and the true current direction is the same.
The type of equivalent transistor is the type of the first original