Capacitance

Capacitance is short term energy storage. It can store lots of voltage, but not a great deal of charge. Capacitance is measured in Farads.

EoA
-------  =  C
d

Eo is "epsilon," the permativity of free space...air. It's usually a constant--> 8.85*10^-12 in Coulombs squared divided by Newton Meters squared. The A represents the area of the plates and the d represents the distance between the plates. Thus, A is related directly to Capacitance and d is related inversely.

This keyboard apparently uses capacitance to allow everyone to type whatever they wish. Pressing the key of the letter you wish to type decreases the distance and sends a signal that then allows that letter to be transferred to the screen from the keyboard.

Somehow, I felt that this picture would fit the blogpost.