A Detailed Analysis Of Transistor

Crystal transistor as a common device, is an important cornerstone of modern electronic world. However, the traditional textbooks on the working principle of the story there is a big problem, so that beginners on the working principle of the transistor can not properly understand, feel awkward and confused. The main issues are the following three points:

1. serious separation of crystal diodes and transistors in the principle of the natural link. There is no real explanation of why the triode junctions are biased and produce Ic? This seems to contradict the PN junction unidirectional conductivity emphasized by the diode principle.

2. Why is the collector current Ic in the amplified state only controlled by the current Ib and has nothing to do with the voltage; that is, between Ic and Ib why there is a fixed magnification relationship.

3. Saturated state, Vc potential is weak, why the collector junction will still have a reverse current Ic through.

Problem 1: This method of explanation In step 3, when the cause of the formation of the collector current Ic is explained, Ic is not generated with emphasis on the nature of the carrier, and Ic is generated. Inadequate emphasis on the high potential of Vc role, while also emphasizing the thin base area. This emphasis is easy to mislead. As long as Vc enough large base area is thin enough, collector junction can reverse conduction, PN junction of the one-way conductivity will be invalid. In fact, this happens to coincide with the principle of triode current amplification. The principle of the current amplification of the transistor is precisely required that the Ic and Vc must be independent of the number in the amplified state, and Ic can only be controlled by Ib. You can buy them on electronic components online store.

Question 2: can not be a good description of the saturation of the transistor. When the transistor works in the saturation region, Vc value is small or even lower than Vb, this time there is still a large reverse saturation current Ic, that is, when Vc is small, the collector will still appear reverse conduction phenomenon. This is clearly contradictory to the high potential that emphasizes Vc.

Question 3: Traditional Faith Step 2 is too much emphasis on the base of the thin, but also easy to give such a misunderstanding that the base area as long as the thin enough, the collector may lose the PN junction of the one-way conductive characteristics. This is clearly contradictory with the experience of using one-way conductivity of two PN junctions within the transistor to determine the name of the pin. Even if the base area is very thin, people determine the name of the pin, but also did not find the base area due to thin PN junction caused by a single case of conductive failure. Base area is thin, but the two PN junction of the one-way conductive characteristics are still intact, which makes people have to determine the name of the transistor pin and basis.

Question 4: In step 2, explain why Ic will be controlled by Ib, and why is there a fixed proportional relationship between Ic and Ib that can not be described in detail? Only from the process to emphasize the base of the thin and low degree of doping, can not fundamentally explain the current magnification is because what will remain unchanged. This rule is same as how to test 74hc595 and how to wire ds18b20.

Question 5: split diodes and transistors in the principle of the natural connection, can not achieve the natural transition on the content. And even people have a contradictory concept, the diode principle emphasizes the PN junction forward conductive reverse, and the principle of the transistor is required to reverse the PN junction conduction. At the same time, it can not reflect the crystal transistor and the electronic transistor between the current amplification principle of the historical link.

Now, we have understood that there is a fixed proportional relationship between Ic and Ib in the magnified state. This proportional relationship shows that the current Ic is controlled in a fixed proportion by the current Ib, which is mainly dependent on the internal structure of the transistor.

The problem is simpler for the cut-off state of Ib equal to zero. When Ib is equal to 0, it means that the external voltage Ube is too small to reach the gate voltage of the emission junction. The emission area does not have the emission and injection of the carrier "electron" to the base region. Therefore, And more likely to have current Ic. In addition, from the pure mathematical current amplification formula easier to introduce the conclusion, Ic = βIb, Ib is 0, it is clear that Ic is also 0.