system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: What happens inside that big block thing halfway down all my power cables?

My game consoles and laptop all have them, but I never understood why.  My TV and monitor don't need them, but neither does my desktop computer which I'd imagine would need it if my laptop does.
gpt
Power from the wall is very strong (high voltage) and goes back and forth really fast (alternating current). Big block takes a little bit of that power and makes it weaker (low voltage) and go in one direction only (direct current). Electronics need power that is weaker and goes in one direction only, and small devices don't have room for the big block inside them.