I have a USB charger with an LED bulb that is lit when it’s plugged in to the outlet. When I unplug it it stays illuminated for about 2-3 seconds. How? And why? Please help
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This is entirely normal. The overwhelming majority of modern electronics have inbuilt circuits and batteries to keep running power through them for a short while after they’re unplugged.
I believe this became a thing about 20 years ago when we crossed the line of it becoming cheap enough to run the constant power through these backup systems to offset the potential damage caused by a sudden power loss.
Electronics are riddled with capacitors. Think of a capacitor like a little battery that charges and discharges is electricity quickly
LEDs require very little electricity.
There’s enough juice in the capacitors to keep that led on for a few seconds until the capacitors discharge.
It still has power running through it, enough to keep the light going. If you unplug it while your phone is still connected on the other end, the light will go out instantly, because your phone sucks up that remaining energy. TVs do it too, the standby light will stay on when it’s unplugged, but try to turn the TV on, and the light will go off right away, as it uses the rest of the power to try and turn on.
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