Mobile phone charger, as an important supporting product of mobile phone, has become an indispensable tool in People's Daily life and work.
The quality of mobile phone charger is directly related to the safety and health of users, so the quality of mobile phone charger attracts more attention.
This paper summarizes the main quality problems existing in mobile phone chargers, analyzes the causes of the problems, and gives guidance to consumers when buying.

The normal use of the situation is basically no danger at all, so what are the possible dangerous circumstances?

1.Charger damage;The explosion?
2.Charger short circuit
3.There is a loud sound of electric current when charging
4.Charger cannot charge
5.Charger heating

1, The charger is damaged, the most is two cases, the first is the explosion of the capacitor, the movement is relatively large, because it is a switching voltage regulation, once this part of the circuit has a problem, the voltage is not normal, the most direct is the explosion of the capacitor.
The second is the transformer explosion, which is caused by the load, because most chargers are false, most have no feedback and protection circuit, transformer explosion is very common.
As long as the water is not damaged, these two are generally not too dangerous to people, but due to the miniaturization of many chargers, high pressure and low pressure are close to each other, and there is no sufficient physical isolation in many chargers. The energy of exploding a capacitor can easily lead to the dislocation and adhesion of the components inside, thus causing danger.

2、Charger short circuit.

The miniaturization trend of mobile phone chargers is very obvious. Compared with traditional large-sized transformers, the current chargers mostly use very small high-frequency transformers, and some of the better chargers also have output feedback.
The value here illustrates a point, whether it's a high frequency transformer or an optocoupler feedback.
One is electromagnetic isolation, one is optical isolation, there is no electrical connection, even if the transformer or other components burned out, under normal circumstances 220V power supply will not string to the phone here, the occurrence of this situation was electrocuted.
The most likely scenario is a short circuit caused by water in the charger.

3. There is a great sound of current when charging.

During the operation of the charger, there will be a slight vibration of the internal devices, so it will emit a sizzling sound.
When the mobile phone is working, due to the resonance of the capacitor, it will also produce a weak sound. There is a transformer in the charger, which is switched in the non-stop opening and closing action.
During the high frequency switch, the coil bobbed up and down due to electromagnetic induction, making a sound.
The "electric sound" is not the sound made by the current itself, but rather the oscillation that allows us to hear sounds visible to the human ear, such as "hissing," "poring," or "buzzing.

The usual cause of an "electric sound" is:
A. Voltage difference
B. Current mutation
C. Frequency resonance

Any conductive material, when energized, will cause mechanical vibration consistent with the frequency of the current.
A wire in alternating current, a light bulb, is actually making noise, but some of the noise is so low that it is hard to hear.

4、The charger cannot charge, which may be due to the following reasons:
1), when the phone does not charge into the electricity, first change a connecting line or a charger, and then try to charge, through the elimination method to see that there is a problem, replace one can;
2) It may be due to the insufficient power of the charger, so you can replace it with a higher power or use the original charger to try charging;
3) Try to plug and unplug the charging cable several times. It may be caused by the poor contact of the data port. Try to clean it with a cotton swab dipped in alcohol.
4), mobile phone use after a period of time, mobile phone batteries can be a problem, not filling into the electricity may be due to the battery aging, if there is a battery power fast not durable, not into electricity, and so on and so forth, is probably due to aging or the battery is a problem, suggest to stop using immediately and find after-sales maintenance, even if the replacement;
5) The reason for checking the operating system may be that there is an error in the file that records the battery information, which can only be solved by brushing the machine.

5、The reason why the charger is hot:
It is normal for the charger to heat up when the mobile phone is charging, and there is loss in the conversion of AC and DC power. Generally, the charger adopts a switching power supply with high efficiency, but due to its limited volume, there is basically no PFC circuit, so the power factor is less than 0.7, and the rest of the energy is basically converted into heat energy.
It is normal for the charger to be a little hot when charging. As long as it does not smell, it is not necessary to care about it. However, it is best to keep it in a ventilated place, because the heat will accelerate the aging of electronic components.

The following is the solution to overheating charger:
1) Charge in a cool environment.
If your phone charger is overheating, it's best to charge it in a cool environment, such as an air-conditioned room, in the summer.
That way your phone charger won't overheat.
2) Use the original charger.
When charging your mobile phone, you should use the original charger, which will ensure a stable output current and protect the battery.
The original charger will also heat, but will not overheat, there is a protective device.
If your charger overheals, it's fake or not the original.
3) Don't play with your phone while it's charging.
Playing with the mobile phone while charging will cause the mobile phone charger to overheat, because it will work for a period of time more than normal, which will not do to the charger, and will reduce the life of the charger.

4) Don't overcharge.
Generally, it takes about 3 hours for mobile phone to charge the original charger. Do not continue to charge after it is full, otherwise it will lead to overload and overheating of the charger.
Unplug the charger in time.
5) Be careful of surrounding heat sources.
When charging a mobile phone, the charger should be put away from the heat source, such as gas stove, steamer, etc., in order to avoid the environmental temperature is too high, causing the charger to overheat.

6), reduce the number of charging.
If the charger is charged several times a day, it will cause the charger to overheat, so the number of charging should be controlled. Generally, it can be charged once a day or two, which can help prolong the life of the charger.
7) Turn off the phone as much as possible while charging.
This will not only extend the life of the charger, but also protect the phone.