In the waveform controlled rectifier circuit, found within the forward voltage of the thyristor to withstand every half cycle, issuing the first time are the same SCR trigger pulse, which is the control angle α and conduction angle θ are equal, then, single-junction transistor relaxation oscillator exactly how to cooperate with the AC power supply in order to achieve effective control of it? When the AC voltage zero-crossing instant, SCR VS forced shutdown, the relaxation oscillator is energized, they began to capacitor C is charged SCR 2P6M, repeat the process. Thus SCR C106M, AC voltage zero after each SCR 2P4M, relaxation oscillator issued the first time a trigger pulse are the same, this time depends on the resistance of RP and C capacitance. Adjusting the resistance of RP, can change the charging time of the capacitor C, the first time it changed Ug issued, a corresponding change of the control angle of the thyristor, so that the average value of the output voltage across the load RL is changed, to achieve the purpose of the regulator. Triac structure principle and application of construction principles although can be seen as a combination of two ordinary triac thyristor from the form, but in fact it is more than just seven transistors and resistors power integrated devices. Low-power Triac generally use plastic packaging, and some also with a heat plate, l shape as shown in Figure. Typical products BCMlAM (1A / 600V), BCM3AM (3A / 600V), 2N6075 (4A / 600V), MAC218-10 (8A / 800V) and so on. Triac power they use RD91 package. SCR C106D, SCR, are fertile Electronics Dongguan City is provided by Wal-Electronic Technology Co., Ltd. Dongguan City is Wal-Electronic Technology Co., Ltd. (www.dgmydz.com) (www.dgmydz.com) strong, credible, FET and other industries in Dongguan, Guangdong has accumulated a large number of loyal customers. The company better work attitude and constantly improving innovative ideas will lead the electronics are fertile and you hand into the brilliant, for a better future!