Editing Keyboard switch by Hiroshi Hasegawa (section)

==Background==

The three main concerns outlined by Hiroshi Hasegawa were as follow:

(1) If the capacitance is higher than a given value the switch is capacitive-coupled to allow a high frecuency of AC current flow. If lower than the given value, the switch is no longer capacitive-coupled so it is turned off.

(2) [[Keyboard switch by Hiroshi Hasegawa#Images|Figure 1]] shows the changing rate of prior art capacitance when depth of depression is narrow, and increases when depth of depression exceeds a given value. 

(3) For example, if an operating value is set according to depth of depression, then hysteresis is low. Something that must be avoided.