Working principle of field effect transistor
A field effect transistor is a field effect transistor. The heat conduction of minority carriers is also called multipole junction transistor. Belonging to voltage-controlled semi-superconductor parts. It has the advantages of high output resistance (10 8 ~ 10 9 Ω), low noise, low power consumption, large static range, easy integration, no secondary breakdown, and wide sea area for insurance. Bipolar transistor and power junction transistor have become stronger partners.
FET characteristics
Firstly, FET is a voltage control device, and its ID (drain DC) is controlled by VGS (gate-source voltage);
Secondly, the output DC electrode of FET is very small, so its output resistance is very large.
Third, the minority carrier is used to conduct heat, so the measurement stability is better;
Fourthly, the electrical reduction coefficient of the reduction channel formed by it is smaller than that of the reduction channel formed by triode;
Fifth, FET has strong radiation resistance;
Six: because there is no scattered noise generated by scattered minority children, because the noise is low. Task principle of field effect transistorIn short, the task principle of FET is "the ID of the drain-source crossing the channel, which is used to grasp the ID of the opposite electrode voltage formed by the pn between the electrode and the channel". More precisely, the amplitude of the ID crossing the circuit, that is, the cross-sectional area of the channel, is the cause of the opposite change of the pn junction and the expansion and change of the depletion layer. In the non-full sea area with VGS=0, the indicated transition layer does not expand much. According to the VDS magnetic field applied between the drain and the source, some electrons in the source sea area are pulled away by the drain, that is, there is direct current ID activity from the drain to the source. The moderate layer expanding from the gate to the drain will block the whole channel, and the ID will be full. This form is called pinch-off. This means that the transition layer blocks the whole channel, and the direct current is not cut off.
Because there is no self-movement of electrons and holes in the positive transition layer, it is actually insulated, and it is difficult for direct current to move. However, the magnetic field between the drain and the source actually means that the two transition layers contact the lower part of the drain and the gate, because the high-speed electrons pulled by the drift magnetic field pass through the transition layer. Because the strength of the drift magnetic field hardly changes, the whole scene of ID appears. Secondly, VGS changes to a negative position, so that VGS=VGS (closed). At this time, the transition layer will generally change the shape of the whole sea area. Moreover, most of the magnetic field of VDS is applied to the transition layer, and the magnetic field that pulls electrons to the drift position cannot stop DC power as long as it is close to the short whole of the source.
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