Pressing on the piezoelectric buzzer in the background causes a current
to flow and the neon bulb in the foreground to glow.
One filament of the bulb glows on depressing the buzzer; the other filament
glows when pressure is released.
Here we see a piezoelectric lighter for gas ranges or grills. Each click represents a striking of the hammer onto the peizoelectric crystal to generate current.
Note the arcing that occurs when the trigger is pulled on the lighter.
In this application, force from the sides distorts the crystal resulting
in a displacement of the center of electric charge. This generates a current.
This is the principle of operation of the lighter shown above.
In this application, an electric current/voltage causes the atoms to
move in atomic size units. This causes the movement of the tip in scanning