Only three characteristics SCR anode voltage A removal or anode A, K pressure change between the cathode polarity (AC zero), the only way thyristor converters by low resistance conduction state to a high-impedance OFF state. Once the cut-off thyristor way, even between the anode and the cathode K A again with a positive voltage thyristor C106M, still in the control electrode G and cathode K between there again with a positive trigger voltage before conduction. Way thyristor conduction and cutoff switch is closed and the state is equivalent to a disconnected state SCR C106D, it can be made with a non-contact switch. 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 SCR 2P4M, UBB via potentiometer RP power to charge the capacitor C, the voltage on the capacitor UC rise exponentially. When UC rises to single-junction transistor UP when the peak voltage, single-junction transistor suddenly turned SCR BTA225, are fertile Electronics (certified), SCR provided by the Dongguan City is Wal-Electronic Technology Co., Ltd. Dongguan City is Wal-Electronic Technology Co., Ltd. (www.dgmydz.com) (www.dgmydz.com) is Dongguan, FET leader, over the years, the company is implementing the scientific management, innovation and development, the principle of honesty and trustworthiness, the maximum limits to meet customer needs. Wal-electronics leader in the positive with the staff warmly welcome all inquiries negotiations to create a positive future Wal-electron better.