Detailed information of silicon controlled rectifier

One-way silicon controlled rectifier, two-way silicon controlled rectifier and silicon controlled rectifier (SCR) are short for silicon controlled rectifier. There are several types of silicon controlled rectifier: unidirectional, bidirectional, turn-off and light control. It has the advantages of small size, light weight, high efficiency, long service life and convenient control, and is widely used in various automatic control and high-power electric energy conversion occasions such as controllable rectification, voltage regulation, inverter and contactless switch. One-way SCR is a controllable rectifier electronic component, which can be turned off by an external control signal, but once it is turned on, it cannot be turned off by an external signal, and it can only be turned off by removing the load or reducing the voltage at its two ends. One-way SCR is a four-layer three-terminal semiconductor device composed of three PN junctions. Compared with a diode with only one PN junction, the forward conduction of the unidirectional thyristor is controlled by the current of the control electrode. Compared with the triode with two PN junctions, the difference is that the thyristor has no amplification effect on the gate current. SCR electronic component bidirectional thyristor bidirectional thyristor has the characteristics of bidirectional alternating on and off. The bidirectional thyristor is essentially two anti-parallel unidirectional thyristors, which is a semiconductor device with three electrodes and four PN junctions formed by five layers of NPNPN semiconductors. Because the structure of the main electrode is symmetrical (all led out by n layers), its electrodes are not called anode and cathode respectively like the one-way thyristor, and the one near the control electrode is called the first electrode A 1 and the other is called the second electrode A2. The main disadvantage of bidirectional thyristor is its low ability to withstand the voltage rise rate. This is because when the bidirectional thyristor is turned on in one direction, the carriers in each layer of the silicon wafer have not returned to the off-state position, so corresponding protection measures must be taken. Bidirectional thyristor is mainly used in AC control circuits, such as temperature control, lighting control, explosion-proof AC switch and DC motor speed regulation and commutation circuit.