Way thyristor SCR polarity determination is made of a semiconductor material constituting the three PN junctions, their basic structure, and the equivalent circuit symbols. SCR has three electrodes: the anode (A), cathode (K) and control electrode (G). From the equivalent circuit, between the anode (A) and the control electrode (G) are the two opposite polarity in series PN junction between the control electrode (G) and the cathode (K) is a PN junction. According to the one-way electrical properties of the PN junction thyristor BTA208, Analog multimeter will select the appropriate resistance profile, test poles between positive and negative resistance (same poles, will lead the two exchanged measured resistance value) SCR BTA216, For the pros and cons of a normal SCR, G, K a big difference between the resistance; G, K, respectively, and the positive and negative A small difference between the resistance and the resistance are great. This test result is only, according to this uniqueness can determine the polarity of the thyristors. Unidirectional way thyristor SCR trigger diode characteristic test similarities that have a one-way conductivity, except that the SCR conduction also controlled by the gate voltage. That makes thyristor must have two conditions: should be added between the anode (A) and the cathode (K) forward voltage thyristor BTA312, should be between the control electrode (G) and the cathode (K) plus the forward voltage. When the thyristor, a gate will lose effect. Unidirectional conducting SCR process is illustrated in Figure 2 shows an equivalent circuit to illustrate: PNP emitter tube quite SCR anode (A), NPN emitter tube quite SCR cathode (K) , base of the PNP and NPN tube collector tube is equivalent to the posterior pole associated thyristor control electrode (G). SCR BTA316 | 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!