Precautions For The Power Adapter

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 there is no external load and no current output, so it can also be understood that this voltage is the upper limit of the output voltage of the power supply.
For the case where active voltage regulator components are used inside the power supply, even if the mains voltage fluctuates, its output is a constant value. Like the small transformers on the market, such as power supplies for Walkmans, if the mains voltage fluctuates, The output of the power supply will not fluctuate accordingly.
Generally speaking, the real no-load voltage of an ordinary power adapter is not necessarily exactly the same as the nominal voltage, because the characteristics of the electronic components cannot be completely consistent, so there is a certain error, the smaller the error, the higher the consistency requirements for the electronic components , the cost of production is higher, 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, it will generate a voltage drop inside, resulting in two things, one is to generate heat, so the power supply will be hot, and the other is One is to cause the output voltage to decrease, which is equivalent to the internal consumption.
2. Both are power supplies with the same nominal voltage but different output currents. Can they be used on the same notebook?
The power supply voltage is the same, but 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. In fact, how much current depends on the load when the voltage is the same. When the laptop is running with a high load, the current is higher, and when the laptop is in standby, the current is smaller, and the power supply with a large nominal current has enough current margin. Conversely, there is no problem for someone to use a 56w power supply instead of a 72w one. 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 substitution is feasible in general use. But the power margin of the remaining power supply is very small. Once your notebook is connected to a lot of peripherals, such as two usb hard disks, then the cpu runs at full speed, and there is a base on which a CD-ROM is read at full speed, and at the same time It is dangerous to charge the battery. So it is best not to use a small current power supply instead of a high current power supply.
3. For the same machine, other people's power supply is warm, but mine is always hot. Why?
Don’t suspect that there is a problem with your power supply. First, check what your notebook is doing. Is it like the two USB hard drives mentioned above? The music is playing, the screen is at maximum brightness, the wireless network card is always detecting signals, etc. It is very important to make good use of power management and adjust the working status 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 any accidents?
First of all, what you need to know is that the power supply to the notebook is different from the battery to the notebook.
Battery-powered, the output of the battery is pure DC, very clean, the voltage of the battery is neither possible nor necessary to be designed 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 are connected in three stages, and 10.8V has become a very popular battery voltage. The nominal value of some batteries is slightly larger than the integral multiple of 3.6V, such as 3.7V or 11.2V, etc., which is actually to protect the battery.
For power supply, the situation is more complicated. First of all, it is necessary to further stabilize and filter the added voltage to ensure stable operation when the performance of the power supply is not very good. The stabilized voltage is divided into two parts, all the way to power the notebook. The other way charges the battery, the part that supplies power to the notebook is the same as when the battery supplies power, and the part that charges the battery needs to pass through the charging control circuit of the battery before it can be added to the battery cell. 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 to each unit of the charging control circuit. In the end, the voltage actually applied to the cell will never be the nominal voltage of your power supply. Don't worry.
A suitable power adapter is required to have safety certification, and a power adapter with safety certification can protect personal safety. To prevent electric shock, fire and other dangers.