Night lights that detect light levels are probably flickering so fast that it just appears to be on
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
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That's how all ac powered lights work because the current is constantly alternating.
I was going to protest this, but then I started looking into how ac is converted to dc and realized that it would be cheaper to just let the diodes run on ac.
oh shit, my stoned ass wasn't prepared for this
Indeed, older bulbs work in both directions and the voltage fluctuation isn't visible in the light emitted, because the thermal mass of the filament smooths out the alternating current into a continuous glow.
But LEDs will flicker unless the AC is rectified and smoothed out. Cheap lights will just not come with the circuitry to do this, as you can just hook up the diode directly, the only drawback being it will only emit light some of time. 60Hz is slow enough that you will notice it, however. Especially with movement, it makes reality look like it's running at 60fps.
Even when rectified, unless a capacitor is added to the circuit, LEDs will flicker. AC merely rectified will still have the voltage hitting zero 60 times a second, otherwise.