In this project, we will be looking at a simple LDR Circuit. A LDR is defined as a Light Dependant Resistor; quite self explanatory. We will be using this component, along side a few others, to turn ON a LED when there is no light. Let's get right into it.
Components Required:
1. 9-Volt DC Power Supply
2. BC547 NPN Transistor
3. 1x LED
4. 1x 50k Ohm Resistor
5. 1x 1k Ohm Resistor
6. 1x LDR03
We will be using the BC547 NPN transistor as a switch to toggle the LED ON and OFF. When the Light Dependant Resistor detects darkness, it will send a positive signal to the transistor, turning on the LED. Similarly, if the LDR detects light, a logic 0 signal is sent to the transistor; turning the LED off. Take a look at the circuit schematic diagram to understand how the components will perform this operation.
Circuit Schematic:
Note: 1=collector, 2=base, 3=emitter