Dark Sensor Circuit

Here’s a design for simple dark sensor circuit that can be connected as an input or switch to another circuit. The sensor has three green wires (1, 2 and 3). Wire 2 should always be connected to one of the inputs. If wire 1 is also connected then the sensor acts as a dark sensor. If wires 2 and 3 are connected to the inputs then sensor operates as a light sensor. This is the figure of the circuit;

All circuits are drawn on software such as Crocodile Clips. Using this software the individual components can be joined together on the screen. Once the circuit is drawn its operation can be simulated to see if it works. If it fails it can be corrected on the computer screen and tested again. Using software to test circuit designs saves time as there is no need to physically solder together components. It also saves money as components and materials are not wasted on failed circuits.