Identification and detection of capacitance components

Identification and detection of capacitance components

　　Capacitor is a kind of electrical energy storage components, with charge-discharge characteristics and communication isolation DC current capacity. It is mainly used in power filter capacitor classification, signal filtering, signal coupling, resonance and DC isolation 1.

　　It can be divided into polyester capacitor, mica capacitor, high frequency ceramic capacitor, single chip capacitor, electrolytic capacitor and so on.

According to the installation method

It can be divided into insertion capacitance and patch capacitance.

Three. According to the role of capacitance in the circuit

　　It can be divided into coupling capacitor, filter capacitor, decoupling capacitor, high frequency damping capacitor, resonant capacitor, load capacitor and so on. It can be divided into fixed capacitors, variable capacitors and micro capacitors.

　　The rated voltage is an effective value of the maximum DC or AC voltage that can be increased in the capacitor without damaging the capacitor within the specified temperature range. If the working voltage added to the capacitor is greater than the rated voltage, the capacitor will be breakdown.

parameter

　　The capacitance recognition method is basically the same as the resistance identification method. It can be divided into 4 types: direct notation, literal translation, color marking and digital marking.

(1) direct labeling method

　　The direct labeling method is to mark the main parameters of capacitors directly on the outer surface of capacitors. It is mainly used for high power and high voltage capacitors, such as 10F/16V, 700 YF/50V, etc.

(2) character number method

　　Symbolic notation usually writes the integer part of nominal capacity in front of the capacity unit symbol and the decimal part in the back of the capacity unit symbol. 1m = 1000 x F, 1P2 = 1.2pF, 1n= 1000 fp33 = 0.33 pF, 3u3 = 3.3uf.

(3) color coded method

　　Like the resistance color code method, its unit is the skin method (PF), as shown in Figure 1-1 to 4.

(4) number standard method

　　The digital standard method uses three digit numbers to represent the nominal values of components. Fig. 1-1-4 Color Standard Set is a combination of left and right. The first two are valid numbers, and the third is 10 (n=0-8). When N9 is a special case, 10-1 is in PF.

Fixed capacitor

　　In the measurements, a suitable multimeter block should be selected, and the two pins of the capacitor should be arbitrarily connected to the two pens. The barrier value should be infinite. If the measurement is zero, it indicates the leakage of capacitance or the detection of internal breakdown of electrolytic capacitors.

　　The red surface pen of the multimeter is connected with the negative pole, and the black pen is connected with the positive pole. At the moment of contact, the multimeter pointer turns right at a larger angle (the larger the capacity, the larger the capacity, the greater the swing), then gradually turns left until it stops at a certain position. Resistance is the positive leakage resistance of electrolytic capacitors, which is slightly larger than the reverse leakage resistance. Practical experience shows that the leakage resistance of electrolytic capacitors should be more than a few hundred kN, otherwise it will not work normally. In the test, if the positive and reverse charge is not charged, that is, the needle does not move, the capacitance disappears or the internal circuit breaks; if the measurement resistance is very small or zero, the capacitance leakage or damage, and identify and detect. The active 3 inductor can no longer be used.

　　Components with self-inductance are called inductors (inductors), and mutual inductance inductors are called transformers, which play the role of AC voltage conversion, current conversion, power transfer and impedance conversion in electronic products. They are electromagnetic induction made of insulated conductors, such as enameled wires, shielding wires, etc. Stress element

　　Inductors are usually classified by skeleton, winding, shielding, packing material, magnetic core or magnetic core.