system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why I can't charge my laptop with an usb cable and a travel adapter like i can do with smartphones?
gpt
Because your laptop requires something around ~~1~~70 watts to operate, and the USB connection only delivers a couple of watts -- maybe 4.5 watts if you use USB 3.0.

Simply put, your laptop requires far, far more power than USB was designed to deliver.