This experiment demonstrates how to build a light-activated relay circuit using a photodiode, transistor, and relay to control a circuit based on the intensity of light falling on the photodiode.
1. Connect the photodiode in reverse bias mode to generate current when exposed to light.
2. Use a transistor as a switch to drive the relay based on the current generated by the photodiode.
3. When the photodiode is illuminated, the transistor will activate the relay, turning on the connected load.
The load (such as an LED or motor) will turn on or off depending on the amount of light falling on the photodiode.
Light-activated relay circuits are commonly used in automatic lighting systems, solar-powered devices, and other electronics projects where light intensity needs to control an electrical load.