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Crystal Three-stage Tube

Aug 30, 2017

               We often come into contact with the crystalline three-stage tube, the use of it is also familiar, relatively speaking to the crystal field effect tube is unfamiliar, but, because the field effect tube has its unique advantages, examples of high input impedance, low noise, good thermal stability, in our use is not uncommon. We know that there are many kinds of field-effect transistors, which are divided into junction-type field-effect tubes and insulated gate-type field-effect tubes according to different structures. The Insulated gate-type field-effect tube is also known as the metal oxide conductor field effect tube, or the MoS field effect tube.Tube

               Because the input impedance of the insulated gate field effect tube is very high, it is the advantage of it, But there are new problems in use. Because of the high input impedance, when a charge object is near the gate, the charge that is induced by the gate is very difficult to release through the resistance. The accumulation of charge caused a rise in voltage, especially in the case of relatively small capacitance, a small amount of charge will produce a higher voltage, so that the pipe has not been used or in the welding has been penetrated or the occurrence of indicators dropped Of the phenomenon, especially MOS tube, its insulating layer is very thin, more easily breakdown damage.Tube

               To avoid such an accident, the key is to avoid the gate hanging, that is, the grid source between the Poles must maintain the DC path. Typically, a resistor (within 100K) is connected between the poles of the grid source, so that the cumulative charge is not excessive, or a regulator is connected so that the voltage does not exceed a certain value. The 3 electrodes should be shorted during preservation. and placed in the shielding metal box, the pipe welding to the electric road or take down, also should be the first to short-circuit each electrode, the installation of the test used in the soldering iron equipment to have a good grounding, it is best to unplug the power of the electric soldering.Tube