Why the original power adapter is better than not the original ones
Original power adapter to relatively better in theory, but in practice may not feel the difference.
Usually load permitted there is a safe range of input voltage, such as nominal value plus or minus 5%, for example, a lot of 2.
5 inches of hard disk input requirement is 5 v plus or minus 5%.
Laptop, too, if the input voltage is too large or too small will lead to protection circuit action, to stop work.
But before the protective circuit, notebook internal voltage regulator circuit has worked to limit or lower limit, in principle, the life has a certain influence to the device, but at the current point of view, the reliability of electronic components has been pretty good, as long as it is within the scope of design, rarely a problem, life wouldn't be shorter than the life of a laptop, so this is not the most major problem.
Bigger problem may be the display data security, automatic protection and suddenly stop work for a computer is a very frightening, especially many don't have friends of the battery.
Computer sometimes puzzling to restart is also related to this.
For the power of the original manufacturer to access what kind of load, so you can easily calculate the nominal voltage and nominal current.
Nominal voltage shall meet the following two conditions: first, the maximum output current, nominal voltage minus pressure drop power itself, should be greater than 95% of the load voltage required.
Minimum second, output current, voltage minus pressure drop power itself, should be less than 105% of the load voltage required.
However if you use are the original adapter, such as general type transformer and so on, these problems cannot be seriously considered, then the user can only try to think of some way to get from the power supply parameters compatible.
But the internal resistance of each adapter is different, the permissible error of the nominal voltage may be different, under the nominal current output voltage range can be different, even are not necessarily the output ripple coefficient is small enough.
If not carefully measured the relationship between the output power and output voltage, in principle, there is a certain risk, but the risk is very small, because as long as you choose a large enough nominal current of the power supply will not appear the problem of much bigger resistance ripple coefficient can be reduced by laptop internal voltage regulator.
So, although the original power adapter is better than the original, but choose the output current is larger than the original power, usually also will be a problem.