STARBET303 Also called foot switch. One form of mercury light switch uses a sealed glass vial that is tipped by the toggle lever, causing a drop of liquid metallic mercury to roll from one end to the other, bridging a pair of contacts to complete the circuit. When the mechanism passes over the center point, the spring energy is released and the spring, rather than the actuator, drives the contacts rapidly and forcibly to the closed position with an audible "snapping" sound. At that time, the common contact bar is forced in the opposite direction by the compression spring, acting via the actuator bar, thus breaking the connection with the existing contact and making connection with the other contact.|Cinta Untuk Guddan