Use mains power to judge ordinary thyristors

Take a rectifier diode VD, a resistor (500Ω5W) and a light bulb EL (220V, 8~15W). After wiring according to the diagram, turn on the power supply. The light bulb should not light up at this time. Use a multimeter (R×10 or R ×100) black test lead is connected to the control electrode G of VT, and the red test lead is connected to the cathode K. The ordinary thyristor will conduct immediately, and the light bulb should light up. Disconnect the test lead, VT will be turned off when the power supply reaches zero, and the light bulb will go out. If If the blocking voltage of ordinary thyristors is greater than 600V, the VD shown in the figure can be omitted. In addition, safety should be paid attention to during operation to prevent electric shock.