Question

Chapter 24. Capacitance And Dielectrics Problem 24.62 In one type of computer keyboard, each key holds a small metal plate that serves as one plate of a parallel plate, ale led capacitor When the key is depressed the plateparation decreases and the capacitance increases Electronic coby does the change in capacitance and thus detects that the key has been pressed in one particular keyboard, the area of each metal plate is 420 mm and the separation between the plates is 0.740 mm before the key is depressed Part Calculate the capacitance before the key is depressed 180 AED ? F Submi Best Ans Part 3 the clocuitry can detect a change in capacitance of 0 250 pF. how far must the key be depressed before the circuny detects is depression? | A20 2 Submit Best Answer

Answer 1

Plate of a key of the keyboard behaves like a plate of the parallel plate capacitor. When the key is pressed the seperation between the plates decreases, so the capacitance increases accordingly.