A photocell, also known as a photoresistor or light-dependent resistor (LDR), is a semiconductor device whose resistance decreases when exposed to light. This simple property makes it a crucial component in many automated systems, from streetlights that turn on at dusk to security systems that trigger an alarm when a shadow passes. Understanding a photocell wiring diagram is therefore essential for anyone working with these types of circuits. A well-implemented photocell circuit can significantly improve energy efficiency and system reliability.
