Introduction to Airfield Lighting Circuits #4

Why are series circuits used in airfield lighting, rather than the more common parallel/voltage circuits?

To cause as much confusion as possible (just kidding). Actually series circuits keep light patterns at balanced brilliancy. By the nature of airports, there are very long distances involved, and it would require very expensive cabling to minimize voltage drops in conventional voltage circuits. Voltage drops in turn would mean varying light brightness, and it is important to avoid this so that a pilot's depth vision is effective. It is far easier to do this with a series circuit since all lamps receive the same current.