2023-04-06
Thyristor, short for thyristor rectifier, is a 4-layer PNPN semiconductor, also known as a thyristor. It has the characteristics of small size, relatively simple structure and strong function, and is one of the most commonly used semiconductor devices. The device is widely used in various electronic equipment and electronic products, mostly used for controlled rectification, inverter, frequency conversion, voltage regulation, contactless switch and so on. Thyristor devices are widely used in household appliances such as dimming lights, speed regulating fans, air conditioners, TV sets, refrigerators, washing machines, cameras, combined audio, acousto-optic circuits, timing controllers, toy devices, radio remote control, cameras and industrial controls.
Thyristor in the circuit can achieve AC contactless control, control large current with small current, and unlike the relay control spark generation, and fast action, long life, good reliability. It is used in speed regulation, dimming, voltage regulation, temperature regulation and other control circuits. Today, Li Yang will talk with you about the working principle of thyristor rectifier elements!
For a PNPN-bound semiconductor, whether its left side is set as positive or its right side is set as positive, there is a reverse PN junction (cutoff state) from either side. For example, if the left terminal is positive, then P1N1 and P2N2 are positive, but N1P2 is opposite. In this case, the current cannot be carried on.
Li Yang Semiconductor reminds you here: PN junction has unidirectional conductivity, then we learned before the PNP type and NPN type transistor is how to conduct the current?
Next, we tried to connect the P1 layer of the P1N1P2N2 4-layer semiconductor to the positive electrode of the battery, N2 layer to the negative electrode, and then the positive electrode of another set of batteries to the P2 layer, the negative electrode to the N2 layer, the result of the current through the entire component. Why is this?
First, we treat the 4 layers of P1N1P2N2 as a composite of P1N1P2 layers and N1P2N2 layers. That is, it is regarded as a composite of PNP type transistors and NPN type transistors. For P2N2, as shown in the figure, the forward voltage is loaded, and the movement of electrons and holes occurs.
At this point, all the electrons from the N2 region through P2 into the base region N1 flow into the base region N1 of the upper P1N1P2 transistor. Electrons entering the base region of the upper layer transistor cause the holes in the upper emitter region to move, which further leads to hole diffusion in the collector region P1.
Through the repetition of the above actions, the current conducts the whole component of the thyristor rectifier. For both ends of the PNPN layer, the original voltage can not be switched on regardless of the direction of loading, and the entire component can be switched on by applying a forward voltage to the PN layer in the middle.
The terminal of the P1 layer of the thyristor is called the anode (A), the terminal of the N2 layer is called the cathode (K), and the terminal of the P2 layer is called the gate (G). In other words, the anode-grid can be operated by applying a forward voltage between the grid cathode.
The above is the relevant introduction of the working principle of thyristor. If you want to know more thyristor, you can pay attention to Liyang Semiconductor, which will be updated continuously in the later stage!
