One of the lightbulbs in my bathroom vanity went out, so I got a new LED bulb out of the package to replace.
Didn’t work.
Hmm, so I tried it in a lamp to see if the problem was bulb or the light itself.
Didn’t work in the lamp either. Naturally, I shook the bulb to see if it was the filament (Yes, I know OLD School)
The bulb flashed! It was in my hand! Shook it again. It flashed again.
So I tried it again in the lamp. Did not work.
Tossed the bulb in the trash, it flashed when it touched a beer can!
What is causing it to flash?
BTW, got another bulb from the package and that one works. Did not try to make it flash.
Probably has a bad connection between the internal power supply and the LEDs.
So, the power supply gets charged up when you put it in the socket, but the charge had nowhere to go. Shaking the bulb caused the bad connection to fix itself momentarily, causing the flash.
ETA: most of those lamps have a warranty - you should fish it out of the trash and take it back to where you bought it, and they will give you a new one (hopefully).
Steve Mould explains the phenomenon (with experimental gear and everything).
The cheap circuitry allows stray (even static) electricity to power the LEDs in the bulb. High-quality bulbs have driver circuits that eliminate that.
Not even remotely related to the phenomenon in the OP.
And if the bulb cost $3-$4 and it takes it takes an hour to go back to the store, wait in line and come home–it’s not financially worth it. Of course you can wait until you were going to the store anyway–but there’s a good chance you will forget about taking the bulb the next time you go.
Sure, if you take time off of work or turn down a client to go to the store. But if you go on an evening when you were just going to sit around the house and do nothing that pays money, financially you are ahead by $3-$4 minus the cost of getting to and from the store.
LED bulbs flash randomly because only tiny tiny amounts of power are required to make them flash. It could be that there is a random connection in this bulb: it could equally be a bad driver circuit with enough stored power to give random flashes when capacitively coupled with your hand or random bits of metal.
Username/post combo alert.
mmm