RLOD#53 (2020.11.29) Early-1980s Silec V200

Introduced in the late 1950s, compact cold-cathode discharge lamps derived from high-voltage sign tube technology were used in traffic signals all across France in place of far less reliable and efficient incandescent lamps. The Silec V200 shown here was intended for green signals and it is coated with a manganese-activated zinc silicate phosphor which is excited by the shortwave radiation from a low-pressure mercury vapor discharge burning in a non-Penning neon-argon buffer mix. The latter is designed to ensure an optimum light output over a broad temperature range, especially towards lower temperatures when the mercury density drops significantly. The V200 was used in Silec's popular Astron fixture which was produced from 1980 to 1996. It is driven at 25 mA with a basic leakage-flux neon sign transformer that enables a reliable and instantaneous discharge ignition as required for the application. The use of cold hollow electrodes ensures a long lamp life unaffected by the frequent switching and the vibrations caused by traffic, operating conditions that would kill a hot-cathode fluorescent tube very quickly. This lamp type was eventually phased out in the early 2000s when LEDs became firmly established in commercial and traffic signage applications.