This is something I have benn curious about and I should probably know but I don't so I have Googled but don't find anything...
I'm talking about an ordinary household lamp dimmer connected to an ordinanary incandescent light bulb.
Starting with it all the way off, if you slowly turn it up, nothing happens at first, then you get past the threshold and the bulb suddenly comes on at say 25% brightness. Now you can turn it back down from there to say 10% brightness. Why does the system exhibit this threhold effect? In other words, you can't simply turn it up to 10%, you have to first go up past the threshold and then back down.
Is it related to the resistance of the bulb changing?
Would the same thing happen with a constant resistance load?
Mark