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What are the manifestations of damage to electronic components? Fault characteristic analysis

Although there are a large number of electronic components in electrical equipment, their faults are regular. What are the manifestations of damage to electronic components in daily work? Next, let's take a look at the analysis of fault characteristics.

1. characteristics of resistance damage

Resistance is the most numerous component in electrical equipment, but it is not the component with the highest damage rate. Open circuit is the most common resistance damage. It is rare that the resistance becomes larger and smaller. Common types include carbon film resistance, metal film resistance, wire wound resistance and fuse resistance. The first two types of resistors are most widely used. Their damage characteristics are as follows: first, the damage rate of low resistance value (below 100 Ω) and high resistance value (above 100k Ω) is high, and the damage of intermediate resistance value (such as hundreds of ohms to tens of thousands of ohms) is very little; Second, when the low resistance resistance is damaged, it is often burnt and blackened, which is easy to find, while when the high resistance is damaged, there are few traces. The wire wound resistance is generally used for large current limiting, and the resistance value is small. When the cylindrical wire wound resistor is burnt out, some will be blackened or the surface will be cracked, and some will have no trace. Cement resistance is a kind of wire wound resistance, which may break when burned out, otherwise there is no visible trace. When the fuse resistor is burnt out, some surfaces will blow off a piece of skin, and some will have no trace, but they will never be burnt and blackened. According to the above characteristics, we can focus on checking the resistance and quickly find out the damaged resistance.

2. characteristics of electrolytic capacitor damage

Electrolytic capacitors are widely used in electrical equipment and have a high failure rate. The electrolytic capacitor is damaged in the following ways: first, the capacity is completely lost or reduced; Second, slight or serious electric leakage; Third, loss of capacity or reduction of capacity with leakage. The methods to find the damaged electrolytic capacitor are:

(1) Look: some capacitors will leak liquid when they are damaged. There will be a layer of oil stains on the surface of the circuit board under the capacitor or even on the surface of the capacitor. This kind of capacitor can never be used again; Some capacitors will bulge after being damaged, and such capacitors cannot be used any more;

(2) Touch: some electrolytic capacitors with serious leakage will be heated after startup, and even hot when touched with fingers. Such capacitors must be replaced;

(3) There is electrolyte inside the electrolytic capacitor. Long time baking will dry the electrolyte and reduce the capacitance. Therefore, focus on checking the capacitance near the heat sink and high-power components. The closer you are to it, the greater the possibility of damage.