Hi again,
There are different types of memristors apparently, and none of the dictionaries known any of them
The dont even know how to spell 'memristor' yet
Anyway, there are different types of memristors but to understand them basically all you have to do
is think of a device like a resistor whos resistance changes based (sometimes) on the history
of another parameter that is associated with the device. In other words, it would be almost
like measuring one parameter that changes naturally and using that measurement to force another
parameter to change. That's such a general statement i know, so here is a simple example of
a charge controlled memristor...
There is a little guy sitting next to a wire and he can see every electron that passes by. He has a
counter in his hand and every time an electron passes from left to right he clicks it up one notch,
and whenever an electron passes from right to left he clicks it down one notch.
The total accumulation on his counter is used to set a variable resistor like a pot. For this
particular memristor the resistance in ohms is equal to the absolute value of the count, so if he
counts up 10 the resistance becomes 10, and if he counts up another 10 that totals 20 so the resistance
is 20 ohms, then if he counts 10 backward the total is back down to 10 so the resistance
again becomes 10. If the count gets back down to zero the resistance goes back down to zero.
The only difference with a real life device like this is that at some point the device would
saturate, and also there would be some time response to consider.
The other interesting thing is that we dont have to assume a linear response. A possibility
is even a 'programmed' nonlinear response that is programmed in such a way as to fit the
application perfectly.
I made an very early type of memristor way back in the 60's when i connected too much
voltage to a relatively small value (1k) resistor. After it turned black it had no
trouble remembering that it went from a 1k resistor to a 500 megohm resistor
Here's a pic of another memristor being manufactured via serendipity again:
And as if that wasnt enough proof that they really do exist, here is a new manufacturing plant for
memristors in live action:
http://www.youtube.com/watch?v=ZTmRjZrS9ZY
LEDs vs Bulbs, LEDs are winning.