718. How does an electric lighter work? - AW
In a piezoelectric lighter, a spring-driven mass strikes a piezoelectric crystal and exposes that crystal to a sudden enormous strain. This strain changes the shapes of the electronic levels in the crystal and produces an imbalance in the electric charges on the crystal's surfaces. One side of the crystal acquires a large positive charge, the other a large negative charge. The potential energies of these imbalanced charges are large enough that they have enormous voltages—typically 10,000 to 50,000 volts. With that much voltage (energy per charge), the charges can leap through the air for about a centimeter or more. If you allow these charges to pass through your hand, they will give you a mild shock—there aren't enough charges moving to give you a dangerous shock.