Super Practical Tips: Inspection Requirements And Methods Of Electronic Components----Semiconductor Devices (2-What Is A Triode 3）

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Field effect classification usage precautions and detection methods: MOS field effect tubes are relatively "squeamish". This is because its input resistance is very high, and the capacitance between the gate and the source is very small. It is easily charged by the induction of external electromagnetic fields or static electricity, and a small amount of charge can form a very high voltage (U) on the inter-electrode capacitance. =Q/C), the tube will be damaged. Therefore, when leaving the factory, each pin is twisted together or installed in metal foil to make the G and S poles at the same potential to prevent the accumulation of static charges. When the pipe is not in use, all leads should also be short-circuited. Extra care should be taken when measuring and appropriate anti-static measures should be taken. Before measurement, short-circuit the human body to ground before touching the MOSFET pins. It is best to connect a wire on your wrist to the earth to keep the human body and the earth at the same potential. Separate the pins again and remove the wires. Set the multimeter to R×100 and first determine the gate. If the resistance of a certain pin and other pins are infinite, it proves that this pin is the gate G. Exchange the test leads and measure again. The resistance value between S and D should be several hundred ohms to several thousand ohms. At the time when the resistance is smaller, the black test lead is connected to the D pole and the red test lead is connected to the S pole. For the 3SK series products produced in Japan, the S pole is connected to the tube case, so it is easy to determine the S pole. Leave the G pole in the air, connect the black test lead to the D pole, and the red test lead to the S pole, and then touch the G pole with your finger. The meter needle should deflect greatly. The double-gate MOS field effect transistor has two gates G1 and G2. To distinguish them, you can touch the G1 and G2 poles with your hands respectively. Among them, the G2 pole has a larger deflection of the watch hand to the left. At present, some MOSFET tubes have protective diodes between the G-S poles, so there is no need to short-circuit each pin. I won’t go into details about other related knowledge, as long as everyone can understand it.