How to use a multimeter to identify the three poles of the thyristor
The method of identifying the three poles of the SCR is very simple, according to the principle of p-N junction, as long as you use a multimeter to measure the resistance value between the three poles.
The forward and reverse resistance between the anode and cathode is over several hundred kilo-ohms, and the forward and reverse resistance between the anode and the control pole is over several hundred kilo-ohms (there are two p-N junctions between them, and the direction is opposite, so the anode and the control pole are not accessible in both positive and negative directions).
Between the control pole and the cathode is a p-N junction, so its forward resistance is in the range of a few ohms to a few hundred ohms, and the reverse resistance is greater than the forward resistance. However, the control pole diode characteristics are less than ideal, the reverse is not completely blocking state, there can be a relatively large current through, therefore, sometimes measured control pole reverse resistance is relatively small, does not mean that the control pole characteristics are not good. In addition, when measuring the control pole forward and reverse resistance, the multimeter should be placed in the R * 10 or R * 1 block, to prevent high voltage control pole reverse breakdown.
If the measured component cathode and anode positive and negative has been short-circuited, or anode and control pole short-circuit, or control pole and cathode reverse short-circuit, or control pole and cathode broken, indicating that the component has been damaged.
Thyristor is the abbreviation of silicon controlled rectifier, is a high-power semiconductor device with three pN junction of the four-layer structure. In fact, the function of the SCR is not only rectification, it can also be used as a switch to quickly turn on or off the circuit, the realization of direct current into alternating current inverter, a frequency of alternating current into another frequency of alternating current, and so on. Thyristor and other semiconductor devices, it has a small size, high efficiency, good stability, reliable and other advantages. Its appearance, so that the semiconductor technology from the field of weak electricity into the field of strong electricity, become industry, agriculture, transport, military research and even commercial, civil appliances and other aspects of the competition for the use of components.
