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There are three main reasons for not being universal: 1.The interface is different Most laptop power adapter brands have different interfaces, which means that other brands of power adapters cannot be plugged into your laptop for power supply. The interface difference is relatively safe, because at least you will not insert a power adapter that does not match the current or voltage to power the laptop, which may cause damage to the computer hardware. 2.The voltage is different Different brands of notebook computer power adapter voltage is different, for example: under normal circumstances IBM is 16V, Dell is 20V, Hp is 18.5V, Sony is 19.5V and so on. It can be seen that even if the power adapter interface is the same, different brands of laptop power adapters cannot be used for power supply. 3.The current is different Different brands of laptop power adapter currents are also different. For example, under normal circumstances, IBM is 4.5A, Dell is 3.34A, Hp is 2.7A, Sony is 4.1A, etc. In fact, the voltage and current of the laptop power adapter of the same brand are not the same. Therefore, even if the power adapter is used between notebook computers of the same brand, it is necessary to confirm the voltage and current specifications.

When we were using the power adapter, we accidentally fell into the water. Can it still be used? How can I know if the voltage instability caused the electronic product to be damaged because of the water in it? In fact, you can use the following methods to test whether it can be used: 1. If the power adapter has entered water, you can pick up the body and shake it to feel whether there is water in it. If you can feel the water, then it proves that there is a lot of water in it, which will have a greater impact on the circuit of the parts. It is difficult to dry thoroughly. At this time, you can take it apart and repair it as soon as possible. If you can't repair it, you can just throw it away and buy a new one. 2. If you can't feel the water inside by shaking the power adapter, there is still some help. The power adapter can be placed in a ventilated place, under the sun or a desk lamp. In a week or so, most of the moisture ran out. 3. You can try to blow it with the cold wind of a hair dryer for a while, and then bury it in the rice for a day, because the rice has strong water absorption. Take it out a day later, or go to the chemical industry to buy a silicon dehumidifier for further dehumidification. Be careful not to recharge within 2 days, otherwise it is easy to cause problems with the charge of the power adapter. If there are still problems, you can only buy another one.

When the PC power supply is in use, it may be wrongly connected or short-circuited. In addition, the power supply itself may malfunction and cause the output voltage to be abnormal. Therefore, in the design and manufacture of the power supply, safety specifications are a very important part. There are two aspects to the protection of the power supply, one is to prevent other accessories from being burned, and the other is to protect itself from damage. The protection of the power supply to the outside is mainly over-voltage and under-voltage protection, which means that when the output voltage of the power supply is too high or too low to be abnormal, the power supply will stop working. This is very important for the whole machine, because all expensive components, such as CPU, hard disk, etc. are relatively fragile, and it is easy to burn out due to high voltage. To prevent this, it is necessary to monitor each output voltage of the power supply. The power designer's approach is to sample the output voltage through a sampling circuit, and the sampled signal is connected to the control part through a comparator. Once the output voltage is abnormal, the sampling signal will be reflected immediately, and the control part will be notified to shut down. This can effectively protect the motherboard, CPU, memory, hard disk, optical drive and other valuable components. Whether the power supply has fast overvoltage protection is very important for the whole machine. In order to prevent burnout caused by excessive current, the power supply is equipped with a fuse. The main job of the fuse is that when the current is suddenly too large, the fuse will burn out first. As long as the fuse is replaced, the power supply can continue to be used. Therefore, the placement of the fuse is very important and must be designed to be replaceable. Now some manufacturers, in order to save costs, Solder the fuse directly on the PCB (printed circuit board) of the power supply. Once the fuse is burned, the entire power supply will be scrapped together! Do not cut corners in this link! Good power supplies mostly use fire-resistant PCB. When consumers buy power supplies, they can use the heat dissipation holes to find out whether the PCB of the power supply uses fire-resistant materials. Generally, the fireproof material No. 94V0 is used, which can withstand 105 degrees of high temperature. As for the use of 94V1 fireproof material, the temperature that can be tolerated is even higher. In addition, a heat shrinkable film must be added to the outside of each part of the power supply for protection to prevent electronic parts from being short-circuited due to moisture or dust. The safety specification is based on the protection of the life and property of users, and has made strict regulations on the insulation and flame retardancy of raw materials for power supply and electrical products. Products that meet safety specifications not only require the power supply itself to meet safety standards, but also require manufacturers to have a complete safety production and quality assurance system. If not, it is easy to malfunction.

In our daily life, we sometimes encounter some minor problems with the power adapter. Commonly used mobile phone chargers, PC power supplies, and power adapters for some small home appliances are damaged. So how can we design safe, reliable and durable products? 1. Voltage stress The voltage stress of the power supply is an important index to ensure the reliability of the power supply. There are many devices in the power supply that have a specified maximum withstand voltage, such as the reverse withstand voltage of the diode, the maximum voltage of the IC, and the maximum withstand voltage of the input and output capacitors. Therefore, we must consider the maximum voltage that the device has to withstand when designing. Then choose the appropriate device according to the voltage, and finally carry out the actual test to verify. 2. current stress The power supply current stress is often closely related to the thermal stress. For example, the diode current is 5A, but it is the limit parameter under the premise of satisfying the thermal stress derating. Therefore, when we select a device, we must meet the current stress and thermal stress of the device at the same time; on the premise of meeting the thermal stress of the device, selecting a device with a suitable rated current value can ensure the reliability of the power supply. 3. Protection circuit The protection circuit includes input under-voltage protection, input over-voltage protection, output over-current protection, output short-circuit protection and output over-voltage protection. In order to avoid abnormal operation of the power supply when the input voltage is too low, the power supply needs to add input undervoltage protection; to avoid the input voltage is too high, and the voltage stress during the period exceeds the standard, the power supply needs to add input overvoltage protection; to avoid output overcurrent and Short-circuit causes the device to overheat, magnetic saturation and other phenomena. The power supply needs to add over-current protection and short-circuit protection; in order to avoid the power supply's output voltage from being too high and causing damage to the load end of the power supply, the power supply needs to add output over-voltage protection. In addition, EMC, safety regulations and overheating protection are all key factors that affect the reliability of the power supply.