Drakness Detector using 741 opamp IC
The circuit below is darkness detector that is it automatically turns on the LED when LDR senses no light.
LDR is the light dependent resistor when exposed to darkness, a LDR has a tremendous amount of resistance. Depending on the specific LDR in use, its resistance can be anywhere from over 100KΩ to well over 2MΩ. When exposed to bright light, a LDR's resistance drops drastically. Again, based on the LDR, it may be to 5KΩ or below or to about 30KΩ. For any LDR, you can pretty much be sure that the resistance will fall to about 30KΩ when exposed to bright light.
LDR is the light dependent resistor when exposed to darkness, a LDR has a tremendous amount of resistance. Depending on the specific LDR in use, its resistance can be anywhere from over 100KΩ to well over 2MΩ. When exposed to bright light, a LDR's resistance drops drastically. Again, based on the LDR, it may be to 5KΩ or below or to about 30KΩ. For any LDR, you can pretty much be sure that the resistance will fall to about 30KΩ when exposed to bright light.
COMPONENTS REQUIRED :
1.one LM741 IC
2.one LDR
3.Two 100k resistances
4.one 180ohm resistance
5.one 4.7k resistance
6.one LED
7.one 9-12v Battery
