By incandescent bulb, I mean the sort of DC bulb one finds in a flashlight, not an AC bulb in a 110 V lamp. AC current will work either way, but DC won't.
Alas, I am at the Univ., and I cannot access YouTube here. I shall have to go home before I can watch your amazing demo.
I know that LED's will not work with reversed polarity, but again, I do not know why this is. I still, however, feel eminently qualified to continue to use my LED flashlights with impunity.
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Your car won't start if you connect the battery backwards, but don't try this, as you will fry the computer of any modern car. It wasn't good for cars back in the days of 6-volt systems and generators, either, but it is a lot worse on alternator syates, as it destroyed the diode in the alternator as a rule.
That is because diodes and computer chips are polarity sensitive devices. They are supposed to only work one way.
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In agree that this is true with modern cars. But my 1951 Chevy Master Deluxe had nary a diode nor a computer chip nor even a transitor in it, and would not start with the battery in backwards. As I recall, when I purchased a new battery once, the yokel at the station stuck the battery in wrong, and all that was produced was the smell of burning insulation, which continued until the battery was turned around the right way.\
This car had a generator, not an alternator.
A logical mind might have assumed that this would have caused the starter to turn backwards, and yet nothing like this occurred. I have no ancient vehicles upon which to repeat this lame experiment.
Again, my original contention is that most people use equipment every day that they do not understand.
If one were to interview all 600 passengers of a huge airbus, I wager that not one would be likely to explain how it was that this heavy thing could possibly fly. I would think that the Pilot wand Copilot and Navigator might have a clue as to how an airfoil works, though.