场效应管(MOS管)如何判断好坏（How can a field effect tube (MOS tube) be judged good or bad）.doc

场效应管(MOS管)如何判断好坏（How can a field effect tube (MOS tube) be judged good or bad） (I) detection of junction type field effect transistors 1. distinguishing electrode and tube type With a multimeter R * 100 * R file or 1K file, with the black pen connected with an electrode, with the red pen in order to touch the other two electrodes. If the measured one electrode and another two electrode resistance were large (infinite) or resistance are small (a few hundred ohms to one thousand ohms), you can determine the black pen then is gate G, the other two electrodes, respectively is the source and drain D S. In the primary measurement of two resistances with high resistance, the tested tube is P channel junction type field effect transistor. In the primary measurement of two resistances with low resistance, the tested tube is N channel junction type field effect transistor. The positive and reverse resistances between any two electrodes of a junction type field-effect transistor may also be measured arbitrarily. If the positive and negative resistances between the two electrodes are equal to several thousand ohms, the two electrodes are drain D and source S, and the other electrode is gate G. The source and drain structures of junction type field effect transistors are symmetrical in structure and can be used interchangeably. If the positive and reverse resistances of a field effect transistor are measured to be 0 or infinity, the tube is broken or has been opened. 2. testing its magnification With a multimeter R * 100 files, the red pen is connected with the field effect transistor source S, the black probe connected to the drain electrode D, measure the resistance value between the source and drain after RSD, and then hand the letter gate G, the multimeter pointer will swing to the left or right (the majority of FET RSD the left hand is increased, less number of swing; RSD FET will decrease, swinging to the right hand). As long as the hand has a substantial swing, that the m