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 a general power supply refers to the open-circuit output voltage, that is, the voltage when no load is connected to the outside and there is no current output, so it can also be understood that this voltage is the upper limit of the output voltage of the power supply.
In the case of an active voltage regulator component used in the power supply, even if the mains voltage fluctuates, its output is a constant value. Like a general small transformer on the market, such as a power supply such as a walkman, if the mains fluctuates, The output of the power supply will not fluctuate accordingly.
Generally speaking, the true no-load voltage of an ordinary power adapter may not be exactly the same as the nominal voltage, because the characteristics of electronic components cannot be completely consistent, so there is a certain error. The smaller the error, the higher the consistency of the electronic components. , The production cost is high, so the price is also more expensive.
In addition, regarding the nominal current value, no matter any power supply has a certain internal resistance, when the power supply outputs current, there will be a voltage drop inside, which leads to two things, one is to generate heat, so the power supply will be hot, and the other One is to reduce the output voltage, which is equivalent to internal consumption.
2. They are all power supplies with the same nominal voltage and 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 laptop. 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 the notebook because the current is too large. In fact, the current depends on the load when the voltage is the same. When the notebook is running under high load, the current is larger, and when the notebook enters the standby mode, the current is smaller, and the power supply with large nominal current has enough current margin. On the contrary, some people use a 56w power supply instead of 72w to use it without any problem. The reason is that usually the design of the power adapter leaves a certain margin, and the load power is less than the power supply, so this kind of replacement is feasible in general use. But the remaining power margin is very small. Once your notebook is connected to many peripherals, such as two USB hard drives, then the cpu runs at full speed, and there is a base on which an optical drive reads the disk at full speed, plus simultaneous It is probably dangerous to charge the battery. So it is best not to replace the high current power supply with a small current power supply.
3. The machine is exactly the same, and someone else’s power supply is warm, mine is always hot, why?
Don’t suspect that your power supply is wrong. First, see what your laptop is doing. Is it the two USB hard drives as mentioned above, the CPU runs at full speed, the hard drive reads and writes at full speed, the optical drive reads the disk at full speed, while charging the battery and putting it loudly With music, the screen is brightest, 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.
First of all, it is important to know that the power supply to the notebook is different from the battery to the notebook.
Powered by battery, the output of the battery is pure DC, which is very clean. The voltage of the battery is neither possible nor need to be designed high. The chemical characteristics of the lithium battery determine that the output voltage of a battery 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 an integer multiple of 3.6V, such as 3.7V or 11.2V, etc., in fact, to protect the battery.
Power supply, the situation is more complicated. First, the added voltage needs to be further stabilized and filtered to ensure stable operation in the case of poor power performance. The stabilized voltage is divided into two parts, and the notebook is powered all the way. The other way is to charge the battery. The part that supplies power to the notebook is the same as when the battery is powered. The part that charges the battery needs to be added to the battery cell through the battery charge 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. Finally, the voltage that is actually added to the battery cell will never be the nominal voltage of your power supply. Don't worry.
