system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why does my laptop still have a huge box on the power cord?  Every other part has gotten smaller but I still have to carry around a big chunky box of a power cable.

Laptops are tiny now compared to just a few years ago but the box on the power cord is still about the same size.  Is there just no demand or is there something about the power cord that makes it impossible to get any smaller? Why can't it be the size of a quarter?  Thanks.
gpt
This is because it's an adapter that reduces the voltage from the power source to the voltage required by the laptop. To do this, a small transformer is required (the chunky box) and this has to contain two coils of wire of certain sizes to convert the voltage from X to Y. Until transformer technology is re-invented to become more compact, the chunky box on the charger lead will always be present.