The failure characteristics of electronic components
1.'s Damage resistance characteristics
Resistance is the electrical equipment in the largest number of components, but not of the highest failure rate of components. Damage resistance to the most common way, the larger resistance rare, small resistance quite rare. There are common carbon film resistors, metal film resistors, wound resistance and resistance of several insurance. Resistance of the first two most widely used, the damage to the characteristics of the first low-resistance (100Ω below) and high resistance (100kΩ or more) of the failure rate high, intermediate resistance (such as Europe and a few hundred to several European Region), Little damage; second, low-resistance resistance when the damage is often charred black, it is easy to find, and high-resistance resistance when very few signs of damage. Wound resistor normally used for high-current limiting, not resistance. Burn wound cylinder resistance when some will be black or skin surface burst, crack, and some did not mark. Cement is the resistance of the resistance of a wound, burn may be broken, otherwise there is no visible trace. Insurance resistance will burn the surface some time to blow up a piece of paper, some no traces, but will not be charred black. Based on the above characteristics of resistance in check may be emphasized, to find out quickly the damage to the resistance.
2. Electrolytic capacitor damage characteristics
Electrolytic capacitors in the electrical equipment of a large quantity, high failure rate. Electrolytic capacitor damage to the performance of the following: First, the total loss of capacity or smaller capacity; The second is minor or serious leakage; Third, the loss of capacity or the capacity of both small leakage. Damage to find ways of electrolytic capacitors are:
(1) to see: some damage when leakage capacitance, capacitance of the circuit board below the surface of even the appearance of capacitance will have a layer of oil, the capacitor can not be discarded; some damage will be to muster the capacitor, which can not be capacitance Continue to be used;
(2) touch: After the start some serious leakage of electrolytic capacitors will be fever, a finger touch even when hot, this capacitor must be replaced;
(3) electrolytic capacitors are internal electrolyte, the baking time will dry electrolyte, resulting in reduced capacity, so the focus should check heat sink and high-power components in the vicinity of the capacitor, from its more recent, damage The greater the possibility.
3. Second, semiconductor devices, such as damage to the transistor characteristics
Second, the transistor damage to the PN junction is a general breakdown or road, with mostly short-circuit breakdown. There are also two types of damage to the performance: first, thermal stability deteriorate for the performance of the boot to normal work after a period of time, the soft breakdown; and the other is the PN junction of the characteristics of variation, R × 1k multimeter test, The PN junction are normal, but after the last machine does not work, if R × 10 or R × 1 low-profile measurement range, will find its PN junction are major resistance than normal. Second, measurement, the transistor can be used in the multimeter indicators measuring the way, a more accurate way is to: Home multimeter R × 10 or R × 1 file (usually with R × 10 files, and then was not obvious when the file R × 1) in road test Second, the PN junction transistor is, the reverse resistance, if the resistance are not too large (as opposed to the normal value), large enough to reverse resistance (as opposed to a positive value), indicating that the PN junction normal, on the other hand is doubtful, to be welded After the next test. This is because in general the Second Circuit, the external transistor resistance in most of the hundreds of thousands more in Europe, multimeter with low resistance measurement of the way in the file, you can ignore the basic resistance of the external PN junction resistance.
4. IC damage to the characteristics of
The internal structure of complex integrated circuits, a lot of features that any part of the damage can not work properly. The circuit also has two types of damage: the total damage to the thermal stability of the non-performing. The total damage, and can be removed with the normal model with its integrated circuit test comparison of each pin is on the way, the reverse resistance, which can always find a pin or a few abnormal resistance. Thermal stability of the poor, the device can work with ethanol is suspected of cooling circuits, if the delay or failure is no longer a fault can be found. They are typically replaced with new circuits to rule out the possibility.
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