MARTYN F. CHILLMAID / SCIENCE PHOTO LIBRARY MARTYN F. CHILLMAID / SCIENCE PHOTO LIBRARY
Street lighting with photoelectric switch. The switch (red, top of light) is sensitive to light. As the light levels fall as the Sun sets (as seen here), the switch triggers the street light and turns it on. A photoelectric switch uses an LDR (light-dependent resistor).
Model release not required. Property release not required.