Power adapter  is the power supply equipment transform for small portable electronic equipment and electronic appliances, generally consists of a shell,power transformer and rectifier circuit.According to the type of output ,it can be divided into AC output type and DC output type; According to connection ,it can be divided into the plug wall and desktop. Widely used in telephone composite machine, game machine, language repeater, Walkman, notebook computer, cellular phones and other devices. 

In some cases, suddenly the notebook battery power shortage, and no power adapter, this situation is very worrying and embarrassing. Some friends may try to borrow another notebook power adapter, but we must pay attention to, different brands of notebook computer power adapter is not universal. 

There are three main causes:

First,different interface .The interface of most notebook power adapter brands are different,different  interface is relatively safe,cause at least you will not plug in the power adapter which not comply with current or voltage of the  notebook computer , leading computer hardware damage.

Second,voltage varies .Different brands of notebook ,the power adapter voltage is not the same .For example: General IBM is 16V, Sony is 19.5V.Even if the same power adapter interface ,nor can different brands of notebook power adapters be used to power the system .Third,current different .Different brands of notebook power adapter current is also different, for example:general IBMis 4.5A,Sony is 4.1A.Even if the same brands but different notebooks also need confirm the voltage and current specifications ,when using the power adapter to charge.

As for the notebook power adapter heating problem, regardless of any power supply have a certain resistance.Therefore when the output current of the power , will produce pressure drop inside, resulting in two things :one is the heat generated, so the power will be hot ;the other is  caused reduction in output voltage, equivalent to internal consumption .But when the longer you use and the greater working load of it ,the greater heat will be send out.