How to use single-junction transistor SCR trigger circuit? We draw separate single-junction transistor relaxation oscillator circuit (Figure 8). It consists of a single-junction transistor and RC charge-discharge circuit composed. After closing the switch S, the power UBB via potentiometer RP to charge the capacitor C, the voltage on the capacitor UC rise exponentially. When UC unijunction transistor rises to a peak point voltage UP when the unijunction transistor suddenly turned in the plot controlled rectifier circuits, the forward withstand voltage of the SCR each half cycle of discovery, issued first trigger always have the same pulse SCR BTA412Y, which is the control angle α and conduction angle θ are equal, then the single-junction transistor relaxation oscillator how to accurately fit the AC power source in order to achieve effective control? In order to achieve the rectifier circuit Output voltage "controlled", must withstand the forward voltage of the thyristor within each half cycle, the trigger circuit to send the first trigger pulse is the same all the time, this way of working with each other SCR BTA216, called trigger pulse and power synchronization. How can we synchronize? We look at the regulator circuit diagram (Figure 1). Note that, here unijunction transistor relaxation oscillator power is taken from the output of the bridge rectifier circuit full-wave pulsed direct voltage. When the thyristor SCR BTA140 when not turned on, the relaxation oscillator capacitor C is charged power, UC exponentially rises to a peak point voltage UP, unijunction transistor VT conduction, in VS conduction period, the load RL the AC voltage and current, at the same time, VS turned down the voltage across the small, forcing the relaxation oscillator to stop working. SCR BTA412Y | 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!