Exactly the same machine, other people's power supply is warm, mine is always very hot, why?

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.

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.

Among them, VT is the switch tube of the power adapter, which is controlled by the excitation pulse and works in the cut-off and saturation state. C1 is the filter capacitor in the mains voltage rectification filter circuit. VD is a freewheeling diode, and its function is to provide a power supply path for the load when the switch is turned off. L is the energy storage inductance (ie switching transformer). C2 is the filter capacitor at the output end of the power adapter.

During the saturated conduction period of the switch tube VT, the DC voltage Ui of the positive pole of C1 is charged through L→VT→the positive pole of C2→the negative pole of C2. On the one hand, a DC voltage is established at both ends of C2, and on the other hand, the magnetic energy in the energy storage inductor L is continuously increased. When the switch tube VT is turned off, L induces left negative and right positive voltages, and the magnetic energy in L is released to C2 and the load through the freewheeling diode VD. The level of the voltage Uo at the output end of the power adapter is determined by the length of the saturated conduction time of VT, that is, the width of the base excitation pulse. The width of the base excitation pulse is determined by the error sampling and amplifying circuit.