可控硅從外形上分主要有螺旋式、平板式和平底式三種，螺旋式的應用較多。 可控硅有三個電極---陽極（A）陰極（C）和控制極（G）。它有管芯是P型導體和N型導體交迭組成的四層結構， 共有三個PN結。可控硅和只有一個PN結的硅整流二極度管在結構上迥然不同。可控硅的四層結構和控制極的引用， SKKT172/12E. SKKT172/14E SKKT172/16E SKKT172/18E SKKT210/08E SKKT210/12E SKKT210/14E SKKT210/16E SKKT210/18E SKKT213/08E SKKT213/12E SKKT213/14E SKKT213/16E SKKT213/18E SKKT250/08E SKKT250/12E SKKT250/14E. SKKT250/16E SKKT250/18E SKKT253/12E SKKT253/14E SKKT253/16E. SKKT253/18E SKKT273/12E. SKKT273/14E SKKT273/16E SKKT273/18E SKKT280/12E. SKKT280/16E SKKT280/18E SKKT280/20E A100P600-4TI A100P650-4 A100P700-4 A100P800-4 A100P800-4TI A100P1000-4 A150X1-1 A150X15-1 A150X15-4 A150X20-1 A150X20-4 A150X25-4 A150X30-1 A150X30-4 A150X35-4 A150X40-4 A150X50-4 A150X60-4 A150X70-4 A150X80-4 A150X90-4 A150X100-4 A150X125-4 A150X150-4 A150X175-4 A150X200-4 A150X250-4 A150X300-4 A150X400-4 A150X450-4 A150X500-4 A150X600-4 A150X800-4 A150X1000-4 A60X1-1 A60X2-1 A60X3-1 A6