system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: why do I have to wait 30 seconds after I unplug my modem to plug it back in? Once it's off, isn't it just...off?

When resetting a modem, why does the 30 second time limit matter?
gpt
Electronics contain capacitors and will maintain a capacitive charge for some length of time. The 30 second window is intended to be enough to let that capacitive charge drain. Not starting discharged can lead to some sequencing problems as the modem powers back up. In a perfect world they'd be designed such that it wouldn't matter, and it usually probably really doesn't.

You can see it one some electronics when you unplug them and the LED slowly fades out rather than going blank entirely.