Automatic indicator for horizontal position - uses two mercury switches whose simultaneous open or closed condition electrically actuates acoustic or visual indicator

摘要

Two mercury switches (15) are mounted, at their switching limit positions, in a device so that only when the latter is horizontal are both switches open. The switch condition signals are routed to an information processing block (12) incorporating a NOR gate, to indicate when the horizontal position has been attained. When the information processing blocks senses signals indicative of both switches being open it provides a visual or an audible indication (13). The use of a low pass filter (26) in the signal path ensures that an indication is provided only in a stable situation.