Part 7/10:
When light hits the photocell, its resistance diminishes, allowing a heater circuit to operate and warm up the switch. If the light persists long enough, the switch opens due to excessive heat, effectively turning off the connected streetlight.
The Efficiency Trade-Off
What’s interesting is the operational cycle of these controls. Although they consume power to function—a necessity to ensure efficiency in controlling heavier loads—the power used is still justified by the overall energy savings deployed in lighting applications.