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?
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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.
Same as why a light on battery starts to get weaker and weaker untill it stops. The energy difference between + and – gets lower so their is les current flowing and therefore the signal (infra red light) gets emitted with less power.
The real world isn’t binary, hardly any of the time. The real world is analog all day long.
Your remote control wants to send a flashing light signal to the TV. The electricity from the battery powers an LED that lights up. As the batter is producing less than it’s rated electric current, there isn’t enough light to make the LED light brightly. But, it’s enough to make the LED light dimly. That dim LED might be bright enough for the TV to see and understand it, some of the time, if it’s held closer, …
Why does your car get weak when you start running out of gas?
On a conventional TV remote, when you press a button, you’re just completing a circuit for something that controls a non-visible light at the end of the remote. In the same way that a flashlight will get dim as its batteries die, the light on the remote won’t be as strong when the batteries start to go for it. As the light gets weaker, the TV can’t necessarily see it as easily.
Probably 99% of TV remotes out there operate on infrared light: There’s a little infrared LED in the top of the remote, and the TV / Blu-ray player / streaming box has a little infrared receiver.
The remote communicates its commands to the TV by quickly flashing the LED in a pattern, vaguely like morse code.
So, when the batteries get weak, what can happen is that the LED isn’t shining as bright, or the LED driving circuit can’t get enough power to flash the full command code.
It is the taper of effect from batteries not being able to provide the necessary power. Unlike your tv where if you cut the power the tv instantly switches off the remote continues to receive power from the batteries but not enough to work properly. The same thing occurs with toys where as the batteries drain the sound becomes distorted and diabolical sounding.
The remote control consists of three components, besides the battery:
* The buttons, which are electrical switches that can be on or off
* The microcontroller, which can either have enough power to work, or not
* The infrared-emitting LED, which sends signals to the TV
Of these, only one of them can get stronger or weaker, rather than just being OK or completely failing: the infrared LED. It will get weaker if the battery cannot provide enough power, which happens when the battery starts to run down. The other components will either work 100% or fail 100%; the infrared emitter is the only part that can “kinda-sorta” work.
A Drop in voltage, lower voltage means lower power and therefor lower strength of the remotes signal
You know how a flashlight gets dimmer when the batteries get weak? It’s identical but it’s an infrared light sending the signal.
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