What Is a Darlington Transistor?
Darlington is just the name of a triode connection method. There are a finished Darlington or a Darlington consisting of two independent transistors. The two-stage amplifier element is also an NPN transistor. The pole current is directly introduced into the base of the next stage and used as the input of the lower stage. Because the same type of transistor is used, it is called a "homopolar Darlington" connection. The use of NPN and PNP transistors connected in series to achieve Darlington's characteristics is called "heteropolar Darlington".
- 1. High current gain;
- 2. The voltage gain is approximately equal to 1 (less than 1);
- 3. High input impedance;
- 4. Low output impedance;
- 5. The magnification is equal to the product of the two tubes, the leakage current has a great effect, causing the circuit to be unstable.
- "Darlington" refers to the combination of two triodes together. There are four types of combinations: NPN and NPN tubes, PNP and PNP tubes, NPN and PNP tubes, PNP and NPN tubes. The current amplification factor of the combination of the two tubes is equal to the product of the current amplification factors of the two tubes. For example, if the magnification of both tubes is 100, then the combination is 100 × 100 = 10000. Darlington tube can be used not only as a switch, but also as an amplifier. [2]
- Darlington is a combination of two triodes according to the direction of current flow. Its advantage over ordinary triodes is that the magnification is higher. The specific magnification is equal to the multiplication of the two triodes. It is often used in power amplifiers and regulated power supplies to reach Linton.
- The disadvantage of the Darlington switching transistor is that the output voltage drop is one more stage than that of a general switching transistor, which is the sum of the two transistor output voltage drops. Because the power of the first stage transistor is small and the output voltage drop is generally large, the output voltage drop of the Darlington switch transistor is about 3 times that of the ordinary switch triode. When using it, pay special attention to whether it generates high temperature. In addition, the adverse effect brought by the high magnification is easy to be interfered. When designing the circuit, pay attention to the relevant protective measures.
- Darlington triode has high current gain! Voltage gain is approximately equal to 1, high input impedance, low output impedance and good switching characteristics, so it is widely used in high power switches, electric hammer drive, pulse motor drive and inductive load switches.
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