system
Given the following post, respond as if you're commenting on Reddit:
human
How do electronics keep track of time when they are turned off/ out of battery?

My iPod died a few months ago and was completely without power until a few days ago when I plugged it in. When it opened it was down to the second. It also wasn't connected to wifi. How does it keep track?
gpt
Small on-board battery whose sole purpose is to maintain a few critical pieces of information and keep track of passage of time. If the on-board battery dies, the clock resets. (This is why ancient PCs always come up with date set to 1907 or 1970 after reboot.)