Electric light flashing unit - uses expansion and contraction of air due to heating, and mercury switch

摘要

The unit has a container (1) with an opening (4) and made of an electrically conductive material. The container (1) holds a fluid, eg. a non-electrically conductive gas such as air and is heated by an electric current if the container may provide sufficient electric resistance, or a wire resistor may be wound around the container. A liquid conductor, such as mercury (3), closes the opening (4) in the container (1) by capillary action. When current flows, heating of the container (1) provides expansion of the air in the container, and an increase of pressure which pushes the mercury away from the container (1), thus opening the circuit. When current is not flowing, the mercury in contact with the container (1) closes the circuit.