Diodes mainly by PN junction and work. PN junction and indivisible point-contact and Schottky type, are also included within the scope of a general diode. Including these two models, including, according to the characteristics of PN structure made plane, the crystal diode classified as follows: point-contact point contact diode is on a single wafer of silicon germanium or a metal pin contact pressure, and then by the current Method formed. Thus, the diode, the capacitance of PN junction, suitable for high-frequency circuits. However, compared with the junction type, point-contact diode forward characteristics and backward characteristics are poor, therefore, can not be used for large current and rectification. Because the structure is simple, it is cheap. Voltage and current of the diode is not linear, so when different diodes connected in parallel to resistor adapted. Characteristic curve PN junction as a diode having one-way conductivity. Typical silicon diode voltage characteristic curve (Figure). Plus a diode forward voltage, when the voltage value is small, current is very small; when the voltage exceeds 0.6V, the current begins to increase exponentially, often referred to this as a diode turn-on voltage; when the voltage reaches approximately 0.7V, diode in a fully conductive state, commonly referred to this voltage diode conduction voltage, denoted by the symbol UD. For germanium diode turn-on voltage of 0.2V, turn-on voltage UD is about 0.3V. Plus a diode reverse voltage, when the voltage value is small, a very small current, the current value of the reverse saturation current IS. When the reverse voltage exceeds a certain value, the current begins to increase sharply, called the reverse breakdown voltage of diode called the reverse breakdown voltage, denoted by the symbol UBR. Different types of diode breakdown voltage UBR value varies widely, from tens of volts to several thousand volts. Low-power diode N pole (negative), the appearance of most of the diode uses a color circle marked out, some diodes diode special notation P pole (positive) or N-pole (negative), there is also the symbol flag is "P "," N "to determine the diode polarity. Positive and negative light-emitting diode can be identified from the pin length, long legs is positive, 55C series diodes, short legs is negative. When using a digital multimeter to test a diode, a positive 0.5W SMD diode, the red pen then the diode, the black pen then negative diodes, 1N4749A diode, when measured resistance is the resistance of the diode is forward, this and Analog multimeter pen then the law is just the opposite. The semiconductor is a material with special properties, it is not as fully conductive conductor, and not as an insulator does not conduct electricity, it is somewhere in between, so called semiconductors. The two most important elements of the semiconductor silicon (read "gui") and germanium (read "zhe"). We often hear of Silicon Valley, it is because there are a lot of family at first semiconductor manufacturers. Diode should be regarded as a semiconductor device family patriarch. Long ago, people are keen to assemble an ore radio to listen to the radio, and later was made this mineral crystal diode. 55C series diodes, gold credit (certified), a diode is provided by Qingdao integrity Technology Co., Ltd. Qingdao integrity Technology Co., Ltd. (www.qdjcx.com) is in Qingdao, Shandong diode leaders, over the years, the company is implementing the scientific management, innovation and development, the principle of honesty and trustworthiness, and satisfy customer needs. Ethical Leadership in gold with the staff warmly welcome all inquiries negotiations to create a better future gold credit.