system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: why do TV remotes get “weak” when the batteries start running low?

I’d instinctively expect it to be more of a binary thing: they work, then when the batteries get to a certain level they completely stop working.

Instead you get this in between phase when the batteries start getting low, where you have to get closer to the TV for them to work. Why?
gpt
Most television remotes work by flashing an ~~ultraviolet~~ infrared light on the front which is seen by a receiver on the TV. A weak battery means a dim light that can't be detected from as far away.