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How is the inductance value and its parameters measured for surface-mounted inductors? Methods are important! I. How is the inductance of a surface-mounted inductor measured? 1. In daily use, inductance manufacturers can do the following: ① Build an AC generator with a frequency set at 100Hz, producing a relatively stable voltage of 10V. ② Install this circuit inside a pointer multimeter; by making some modifications to the multimeter, this circuit can be connected in series with the measurement circuit during testing. ③ Use several inductors with known inductance values for testing – those with higher inductance can be used, while those with lower inductance can be used at lower settings. Record the position of the pointer’s deflection; using this as a reference, it is possible to estimate the approximate inductance of surface-mounted inductors. 2. In research institutions: Special inductance testers are used; for inductances of 10nH or higher, a measurement frequency of 10kHz or 1kHz is typically applied. If the inductance of the SMD inductor is relatively low, it is possible to increase the frequency. When used in conjunction with specialized SMD inductor fixtures, the SMD inductor tester achieves excellent contact, resulting in more stable test data. Inductor 1: Color coding method: The color coding method uses color rings to indicate the inductance value, with the unit being mH. Two digits represent the significant figures, the third digit indicates the multiplier, and the fourth digit denotes the tolerance. 2. Direct marking method: The inductance value of the inductor coil, along with key parameters such as the allowable error and operating current, are directly indicated on the coil’s casing using numbers and text. II. How to determine whether a surface-mounted inductor is good or bad? 1. Measurement of inductors: Set the multimeter to the buzzer diode mode, place the probes on the two terminals, and check the multimeter’s reading. 2. Good or bad assessment: The reading for a surface-mounted inductor should be zero at this point; if the multimeter reads a high value or infinity, it indicates that the inductor is damaged. For coils with a large number of turns and a thin wire diameter, the reading can range from dozens to several hundred; typically, the DC resistance of such coils is only a few ohms. The damage is indicated by overheating or obvious damage to the inductor’s magnetic core; if the inductor coil is not severely damaged but it is difficult to determine, its inductance can be measured using an inductance meter, or a replacement method can be used for assessment. III. Precautions for surface-mounted inductors: 1. For inductive components, the core and windings are prone to changes in inductance due to temperature rises; it is necessary to ensure that their temperature remains within the specified operating range. 2、Gap capacitance can also occur between the various windings of an inductor, especially with multiple layers of thin wires; this leads to bypassing of high-frequency signals and reduces the actual filtering effectiveness of the inductor. 3. The winding of an inductor easily generates an electromagnetic field when current flows through it. When placing the components, care should be taken to keep adjacent inductors apart from each other or to arrange their windings at right angles to reduce the amount of mutual induction.