What is the specific working principle of the transistor?

The working principle of the transistor is actually similar to that of the faucet, so it is easy to understand!

A transistor is composed of two N-type or P-type diodes sandwiched between a layer of P-type or N-type diodes, and is divided into a collector, a base, and an emitter. The collector is responsible for replenishing the energy, the base is responsible for trigger control, and the emitter is responsible for output. Due to its special structure, the amount of electrons injected in the emission region is several times the amount of electrons at the base, when the base signal current is turned on, the emitter current emission is triggered, such as the base enters an electron, the emitter may flow out of several or hundreds of electrons, so as to achieve the so-called current amplification.

1) In order to facilitate the emission of electrons by the emission junction, the doping solubility of the semiconductor in the emission region is much higher than that of the semiconductor in the base region, and the area of the emission junction is small.

2) Although the emission area and the collector area are doped semiconductors of the same property, the doping solubility of the emission area is higher than that of the collector area, and the area of the collector junction is larger than that of the transmitting junction, which is convenient for collecting electrons.

3) The base region of the two PN junctions connecting the emission junction and the collector junction is very thin, and the doping solubility is also very low.

The working principle of the transistor: by inputting a small alternating current, a large static direct current is controlled.

Specific principle: The transistor can constantly monitor and flow the current between the base and the emitter, and can control the current source between the collector and the emitter, so that ten to hundreds of times the current between the base and the emitter flows between the collector and the emitter. In other words, the collector-emitter current is controlled by the base current of the transistor.

Categories: Education Science >> Science >> Engineering Technology Science Analysis: How transistors work.

The transistor is a kind of control element, mainly used to control the size of the current, taking the common emitter connection method as an example (the signal is input from the base, output from the collector, and the emitter is grounded), when the base voltage UB has a small change, the base current IB will also have a small change, controlled by the base current IB, the collector current IC will have a big change, the larger the base current IB, the larger the collector current IC, on the contrary, the smaller the base current, the smaller the collector current, That is, the Qixiao base current controls the change of the high and medium current of the collector electrode. But the change in collector current is much greater than the change in base current, and this is the amplification effect of the transistor. The ratio of the change in IC to the change in IB is called the magnification of the transistor ( IC δib, δ indicates the amount of change. The magnification of the transistor is generally in the tens to hundreds of times.

When the transistor amplifies the signal, it must first enter the conduction state, that is, it is necessary to establish a suitable static working point, also known as establishing bias, otherwise it will amplify the distortion.

A resistor is connected between the collector of the transistor and the power supply, which can convert the current amplification into voltage amplification: when the base voltage UB increases, IB becomes larger, the IC also becomes larger, and the voltage drop of IC in the collector resistance RC is also larger, so the collector voltage of the transistor UC will decrease, and the higher the UB, the lower the UC, δuc=δub. FYI, please refer to the relevant books.

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