Why the weight is different?

Why the weight is different?  

In fact,it is obvious that different laptop adapters has different weight.   

Even if eliminating the difference about the main material and heat emission because of different powers, among the same power of original laptop adapters. 

 their weight have almost doubled different.Some third-party compatible adapters are lighter. In this case,the laptop adapter should be heavy enough,to ensure the stability of laptop adapters.  

"The easy people" think that,because the laptop becomes light and slim,adapters need to "ease the burden" too, otherwise,it is really not easy to take. what a absolutely joke is that1KG laptop comes with 500G adapter.  

It should be said,both of them are right. But now, how should we see the light laptop adapters?Please see the two cases to lose the weight as below. One case is The Essence of Concentration.  

Depending on the improvement of circuit and design. the manufacturer use the higher power converted efficiency to decrease the weight of internal heat sink and element.  

so as to reduced volume and weight. Most of original laptop adapters and compatible laptop adapters are do like this,you may rest assured to buy it. Another case is jerry-build,they usually decrease some proper protection(such as PFC circuit). even cut down the material on heat sinks and case.  

The voltage of these adapters lack of stability,even the strength of case is really bad. Please,pay much attention to it when you plan to buy. It is fine to take 19V4.74A adapter intead of 19V3.9A, you only to check if the connector is right. Laptop Adapter is the leading role. Choosing one full power and good stability adapter is the basis of laptop.