High-pressure sodium lamps are high-intensity gas discharge lamps. When the lamp is first extinguished, the internal temperature is very high, resulting in high vapor pressure. While the pulse voltage of the starting device cannot exceed 5,000 volts for safety reasons, it cannot reach the breakdown voltage required for starting at this time. Therefore, the lamp cannot be started when it is hot and must wait until it cools down.
What are different kinds of materials to produce the street light poles? Will they be very different from each other?