A) ordinary diode testing (including the detector diodes, rectifier diode, damping diodes, switching diodes, freewheeling diode) is a PN structure into a semiconductor device having a one-way electrical properties. By detecting its positive and negative resistance value with a multimeter, it can distinguish the diode electrode, but also estimate the diode is damaged. 1. Polarity discrimination would multimeter R × 100 R × 1k file or files, two tables document the two electrodes respectively connected diodes, measure a result, the swap two tables document, and then measure the result. The results of the two measurements, there is a large measure (reverse resistance) resistance, a measure of the resistance is small (for the forward resistance). In a small resistance measurements, diode, black pen then the diode cathode, the red pen then the negative diode. 2. Single negative conductivity detection and the quality of judgment generally, germanium diode forward resistance value of about 1kΩ, reverse resistance value of about 300. Silicon diode resistance value is approximately 5 kΩ, negative resistance value is ∞ (infinity). Forward resistance the smaller the better, the bigger the better reverse resistance. Positive and negative resistance values ??differ more poor, indicating a one-way diode electrical properties better. If the positive and negative resistance values ??were measured diode close to 0 or less resistance, it shows that the diode has a breakdown of internal short circuit or leakage damage. If the measured diode positive, negative resistance values ??are infinite, then the diode is open corrupted. 3. Reverse breakdown voltage detector diode reverse breakdown voltage (voltage value) to test meter to measure the transistor DC parameters. The method is: When measuring diode, should "NPN / PNP" select key test table to NPN state, within and then tested positive diode connected to the test table "C" jack, insert the negative test table "e "socket, then press the" V (BR) "button, the test table to indicate the diode reverse breakdown voltage. Also available megohmmeter and a meter to measure the diode reverse breakdown voltage measurement tested positive phase diode cathode and megger, the cathode of the diode is connected to the positive and megger, LL34 diode, simultaneously with (placed in an appropriate DC voltage profile) voltage across the diode monitor multimeter. As shown in Figure 4-71, shake megger handle (should slow gradually speed up), the voltage across the diode to be stable and no longer rises, 1N5248B diode, the voltage value that is the diode reverse breakdown voltage. Single planar wafer of semiconductor diode (predominantly N type silicon single crystal film), the P-type impurity diffusion using the silicon oxide film surface shielding effect, on the N-type silicon single sheet only is selectively formed by diffusion of a part PN junction. Therefore, no adjustment of the corrosive effect of the PN junction area of ??the drug. Since the semiconductor surface is too smooth production, hence the name. And, PN binding surface, having been covered with the oxide film, it is recognized as a good stability and long life type. Initially, the semiconductor material is formed using an epitaxial method is the use of so called again planar epitaxial planar type. Planar type diode, seem to use the model for large current rectifying small, and for the many small current switching models. Alloy diffusion type diode which is a kind of alloy type. Alloy is easy material to be diffused. The appropriate concentration is difficult to manufacture the material by skillfully blending impurity diffusion can be had with the alloy together in order to obtain an impurity in the PN junction has been formed in the distribution. This method is suitable for the manufacture of high-sensitivity varactor. Epitaxial PN junction diode manufacturing epitaxial surface long process and the formation of the diode. It requires very high technology manufacturing. Because it can freely control the distribution of different concentrations of impurities, it is suitable for the manufacture of high-sensitivity varactor diode. Series regulator circuit (Figure 5): In this circuit, the series regulator BG base is clamped at the Zener diode D 13V, then the emitter voltage of 12V on the output constant in this circuit a lot. occasions are applied. Transistor emitter follower circuit in many electronic circuit, in order to reduce the impact on the front-stage circuit and the output stage circuit requires some front-end circuit has strong load capability (which requires a low output impedance), the use to buffer circuit, so as to achieve before and after class with a load capacity and enhanced impedance matching circuit, 55C18V diode, a transistor emitter follower buffer circuit is the way to achieve the above functions. Transistor emitter follower transistor circuit is actually a total flop, it is a transistor circuit form one of the three (the common base circuit, common-collector circuit, a total flop), which form the basic circuit shown in Figure A1 diode DB3. | The integrity (certified) | diodes provided by Qingdao integrity Technology Co., Ltd. Qingdao integrity Technology Co., Ltd. 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