[introduction] silicon controlled rectifier calls brilliant brake the canal again, with other semiconductor device, have volume small, efficiency tall, stability good, job is reliable wait for an advantage. Silicon controlled rectifier serves as very mature semiconductor device, arrive from weak report emphasize, consume an electron to wait to get applied extensively to industry, can serve as rectification, wait without contact circuit switch and inversion application, this chapter key spreads out an analysis to its structure and equivalent circuit, conduce to a reader deepening the understanding to product of silicon controlled rectifier and acknowledge.

Silicon controlled rectifier from electric symbol photogenic than at diode much a door pole cites a base, come from the function say belong to rectifier, the control that silicon controlled rectifier passes door pole can come true guide of current flow angle adjust. The union that 4 PN written guarantee, can tear open PNP dynatron and NPN dynatron complex structure, among them the base of PNP and NPN collector join, PNP collector and NPN base join, formed lock up loop oneself.

Have enough drive extremely when the door when signal gives, NPN leaving a valve guides a job, PNP is in charge of on the drive electricity that door pole provides NPN collector to give through falling, make on government-owned PNP also guides, lock up the make a present of of positive and negative of circuit through each other, make two dynatron enter saturation to guide a mode, right now already need not exterior continue to provide drive signal. Will look from working principle, silicon controlled rectifier belongs to half control parts of an apparatus, only controallable its are enlightened, the electric current in closing a condition to give priority to loop spends zero hour.

Silicon controlled rectifier divides one-way silicon controlled rectifier and two-way silicon controlled rectifier two kinds. Two-way silicon controlled rectifier also calls 3 end two-way silicon controlled rectifier, abbreviation TRIAC. Two-way silicon controlled rectifier is equivalent to two one-way silicon controlled rectifier joining reversely on the structure, this kind of silicon controlled rectifier has double guide to connect a function. Its open position by the door extremely decision, add on door pole pulse (or negative pulse) can make its to (or retrorse) guide. Next graphs are to the two-way silicon controlled rectifier that rises with retrorse silicon controlled rectifier and both union.

Can see from the structure the combinative means that PN writtens guarantee wants two-way silicon controlled rectifier a lot of more complex, no matter be cathode, zincous,still be door pole, it is by PN two knots are formed at the same time among them, to its working quadrant spreads out below analytic, can understand its job mechanism more easily.

The first quadrant

Two end of door pole and MT1 bring to bear on drive signal, the N structure of the P knot of door pole and MT1 is become guide access diameter, in MT2 and MT1 right now two end bring to bear on to voltage, namely Vmt2-mt1>0, corresponding MT2 P knot intervenes guide, because this made the PNN of from above to below and NPN structure and voltaic way, because this job is in the first quadrant, driving voltage and advocate loop job voltage is together.

The 2nd quadrant

Two end of door pole and MT1 bring to bear on negative drive signal, vmt2-mt1 is among main circuit, equivalent circuit pursues as follows, right now it is thus clear that Vmt1-g of left NPN1 voltage is pressing, right now left NPN1 dynatron guides, go up correspondingly tubal PNP base gets drive signal guides thereby, then NPN2 base gets drive signal guides, right now take out door extremely signal, be in charge of on PNP has formed make a present of of positive and negative to lock up circuit oneself with NPN2 leaving a valve, voltage of the 2nd quadrantal job is negative, driving voltage is.

The 3rd quadrant

Door pole and MT1 continue to bring to bear on signal of negative pressure drive, main circuit Vmt2-mt1 is negative, equivalent circuit pursues as follows, right now NPN1 begins because of the existence of drive negative pressure to guide a job, NPN2 base and NPN1 base are interlinked, connect because of this NPN2 had drive signal and guiding, PNP base guided there is drive report conductance to connect after connecting in NPN2, pull move NPN3 to guide, make a present of of positive and negative is formed to lock up circuit oneself later. Right now the job is in the 3rd quadrant, working voltage and driving voltage are at the same time negative.

The 4th quadrant

Door pole and MT1 bring to bear on to pressing drive signal, main circuit Vmt2-mt1 is negative, equivalent circuit pursues as follows, among them NPN1 is in signal of door pole drive is added hold next guiding to connect, NPN2 base and NPN1 are common, because this NPN2 guides,connect, bring drive electricity to PNP base, same NPN3 guides, form make a present of of positive and negative to lock up circuit oneself thereby, right now door extremely voltage is, voltage of main circuit job is negative.

Commonly used two-way silicon controlled rectifier has two kinds of kinds, 4 quadrant of the standard, optimize model model 3 quadrant, 3 quadrantal silicon controlled rectifier are through be in MT2 end blasts off extremely did special processing, prevent its to guide in the 4th quadrant, rose to change shed ability, bigger to change load, especially perceptual load has bigger Dv/dt change, the misdirect that causes silicon controlled rectifier easily is connected, because this 3 quadrantal silicon controlled rectifier increased to fight sex of a confusion of voices, reduce the demand to protecting circuit, and rise prevent false triggering ability.

Silicon controlled rectifier is out of shape: Sidactor, also call solid discharge canal, it is one kind does not need to spark the silicon controlled rectifier that brings a foot to be able to work.

Silicon controlled rectifier sparks commonly usedly means is door pole to spark, but still a few is not spark heply by person place means, for instance: Tall Dv/dt, temperature sparks, light sparks etc, solid discharge is in charge of even if use the character of silicon controlled rectifier, in spark means was done optimize, because this goes besides to the door extremely the demand that cites a base, the structure is as follows, when working voltage exceeds puncture voltage, solid discharge canal guides, working character follows be struck by lightning commonly used gas discharge tube is similar, regard semiconductor as the product, its are had answer speed fast, leakage current is small, without life attenuation and dependability advanced advantage, commonly used protect at the surge of communication port, and with pressure quick the protection of be struck by lightning that resistor collocation regards power source as input end, can lower residual voltage effectively, have better protective effect to power parts of an apparatus.

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