1. What does the nominal voltage and current of the power adapter (hereinafter referred to as the power supply) mean? First of all, the nominal voltage of the general power supply refers to the voltage of the open-circuit output, that is, the voltage when no load is connected to the outside and there is no current output. Therefore, it can also be understood that this voltage is the upper limit of the output voltage of the power supply.

 

In the case of the use of active voltage regulator components inside the power supply, even if the mains voltage fluctuates, the output is a constant value. Like small transformers on the market, such as the power supply equipped with Walkman, if the mains voltage fluctuates, The output of the power supply will not fluctuate accordingly.

 

Generally speaking, the real no-load voltage of ordinary power adapters is not necessarily exactly the same as the nominal voltage. Because the characteristics of electronic components cannot be completely consistent, there is a certain error. The smaller the error, the higher the consistency requirements for electronic components. , the production cost is high, so the price is also more expensive.

 

In addition, regarding the nominal current value, any power supply has a certain internal resistance, so when the power supply outputs current, a voltage drop will be generated internally, resulting in two things, one is to generate heat, so the power supply will be hot, the other One is to cause the output voltage to drop, which is equivalent to internal consumption.

 

2. Both power supplies with the same nominal voltage have different output currents. Can they be used on the same laptop?

 

The power supply voltage is the same, the output current is different, can it be used on the same notebook. The basic principle is that a power supply with a large nominal current can replace a power supply with a small nominal current. It is estimated that some people will think this way, thinking that a power supply with a large nominal current will burn out the notebook because the current is too large. How much current actually depends on the load for the same voltage. When the books are running at high load, the current is larger, and when the books are in standby, the current is smaller, and the power supply with a large nominal current has sufficient current margin. On the other hand, there is no problem with using a 56w power supply instead of a 72w power supply. The reason is that the design of the power adapter usually leaves a certain margin, and the load power is smaller than the power supply power, so this kind of replacement is feasible in general use. But the remaining power margin is very small. Once your notebook is connected to a lot of peripherals, such as two usb hard drives, then the cpu runs at full speed, and there is a base with an optical drive on it to read the disk at full speed, plus at the same time Charging the battery can be dangerous. Therefore, it is best not to replace the high-current power supply with a low-current power supply.

 

3. The same machine, others' power supply is warm, mine is always very hot, why?

 

Don't suspect that there is a problem with your power supply, first look at what your notebook is doing, whether it is like the two USB hard drives mentioned above, the CPU runs at full speed, the hard drive reads and writes frantically, the optical drive reads the disk at full speed, while charging the battery, playing loudly It is very important to make good use of power management and reasonably adjust the working state of the notebook according to the task.

 

4. The nominal voltage of the power supply is much higher than the voltage of my laptop battery. Will there be an accident?

 

First of all, you need to know that the power supply to the notebook is different from the battery power supply to the notebook.

 

Battery powered, the output of the battery is pure DC, which is very clean. The voltage of the battery is neither possible nor required to be designed to be very high. The chemical characteristics of the lithium battery determine that the output voltage of a cell can only be around 3.6V, so Many batteries use three-stage series connection, and 10.8V has become a very popular battery voltage. The nominal value of some batteries is slightly larger than the integer multiple of 3.6V, such as 3.7V or 11.2V, etc., in fact, to protect the battery.

 

Power supply, the situation is a bit more complicated. First of all, the added voltage needs to be further stabilized and filtered to ensure stable operation when the power supply performance is not very good. The other way to charge the battery, the part that supplies power to the notebook is the same as when the battery is powered, and the part that charges the battery needs to be added to the cell through the battery's charging control circuit. The control circuit can be very complicated, so the power supply voltage It must be greater than the cell voltage to have sufficient capacity to supply each unit of the charging control circuit. The final voltage added to the cell will never be the nominal voltage of your power supply. Don't worry.

 

A suitable power adapter requires safety certification, and a power adapter with safety certification can protect personal safety. To prevent electric shock, fire and other hazards.