rockSlayerApr 1, 2024

Night lights that detect light levels are probably flickering so fast that it just appears to be on

https://lemmy.world/post/13776865

Night lights that detect light levels are probably flickering so fast that it just appears to be on - Lemmy.World

Ok so I got this idea not while showering, but because I’m very high. The story does come from my bathroom though! I have a night light in my bathroom, and I was looking at the night light as I turned off the bathroom light. I’m a big nerd so I remembered that the things that detect light levels are actually diodes wired in reverse. I thought it would be funny to make it flicker by reflecting the light back on the diode, but it didn’t work. That’s when I had this realization

Show threadfidodoApr 1, 2024
That’s how all ac powered lights work because the current is constantly alternating.
Show threadSeptimaeusApr 1, 2024
Alternating current is back-and-forth vs on-and-off. The filaments aren’t rated for rapid strobing, which is why you can easily burn them out by just using a light switch to flicker them too much.
Show threadMentalEdgeApr 1, 2024

While that’s true, in between the voltage spike in either direction there is a moment of equilibrium that is equivalent to “off”.

This moment lasts for too short a time to matter, as the voltage goes up and down smoothly in the pattern of a sine wave, meaning the time spent in the true “off” state is infinitesimally small, not 1/60 of a second as the frequency would suggest.

But even then the filaments temperature does fluctuate with the flips in voltage. It again just doesn’t matter, as it becomes sufficiently energised again before it even cools enough to stop glowing.

Show threadSeptimaeus
This is great detail. Thank you!
Apr 1, 2024 at 7:18amWeb