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2020-09
30
The Field Effect transistor works like this
Field effect tube introduction
FieldEffect Transistor (FieldEffect Transistor (FET)) featured a FieldEffect Transistor. A conductor carried by a few carriers is also known as a multipole junction transistor. It is attributed to the voltage mastering type semi-superconductor mechanism. Deposit is high output resistance (10 ^ 8 ~ 10 ^ 9 Ω), low noise, low power consumption, large static categories, ease of integration, no secondary breakdown task waters wide vision, insurance and other strengths, now change bipolar junction transistor junction transistor and power the growth of the partners.


Field effect tube characteristics
1. The fET is a voltage mastering device, which passes through VGS (gate source voltage) to master ID (drain direct current);
2. The direct current at the output end of the fET is very small, so its output resistance is very large.
3. It USES minority carrier heat conduction, so its measurement stability is good;
4. The small electric reduction coefficient of the shrinking path formed by it is smaller than that of the triode;
5. The field effect tube has strong anti-irradiation power;
6. Because there is no scattered noise caused by scattered children with mixed activities, because the noise is low.


The mission principle of field effect tube
In a word, the fET task principle is "the ID of the drain electrode to the source electrode through the channel, which is used to reverse the electrode voltage control ID constructed by the PN between the electrode and the channel ". To be more precise, the amplitude of ID passing through the circuit, that is, the channel cross-sectional area, is the cause of the depletion layer expansion transition mastered by the reverse transition of the PN junction. In the non-full sea area where VGS=0, the expansion of the indicated transition layer is not very large. According to the magnetic field of VDS added between drain and source, some electrons in the sea area of source are pulled by drain, that is, there is a DIRECT current ID activity from drain to source. The moderate layer expanded from the gate pole to the drain pole will form a block type of all the channels, with full ID. This form is called clipping. This symbolizes that the transition layer will block the channel en bloc, and no direct current is cut off.

Because there is no electron, hole in the transition layer is moving, is in the real form is simply stored in the insulation characteristics, the general direct current is difficult to move. However, in this case, the magnetic field between the drain and the source electrode is, in practice, the two transition layers contact the drain and the lower left of the gate pole, because the high-speed electrons drawn by the drifting magnetic field pass through the transition layer. The strength of the drifting magnetic field has hardly changed to the full image of ID. Secondly, VGS changes to the negative position, making VGS=VGS (off). At this time, the general change of the transition layer covers the shape of the whole sea. In addition, the large magnetic field of VDS is added to the transition layer, which will pull the electrons to the magnetic field of the drifting position. As long as the magnetic field is close to the source pole for a short time, the DC current will not be sluggish.


 
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