Posted by Circuits Arena on Wednesday, 11 May 2016
LDR Based Sunset Lamp-IC NE555 Based Circuit is the artlcle explaining LDR Based Sunset Lamp LDR -based automatic lights flicker due to the change in light intensity at dawn and dusk. So compact fluo...
LDR Based Sunset Lamp
LDR-based automatic lights flicker due to the change in light intensity at dawn and dusk. So compact fluorescent lamps (CFLs) are unsuitable in such circuits as flickering may damage the electronic circuits within these lamps. The circuit described here can solve the problem and switch on the lamp instantly when the light intensity decreases below a preset level. The circuit uses popular timer IC NE555 (IC1) as a Schmitt trigger to give the bistable action.
The set and reset functions of the comparators within the NE555 are used to give the instantaneous action. The upper threshold comparator of IC1 trips at 2/3Vcc, while the lower trigger comparator trips at 1/3Vcc. The inputs of both the threshold comparator and the trigger comparator of NE555 (pins 6 and 2) are tied together and connected to the voltage divider formed by LDR1 and VR1. The voltage across LDR1 depends on the light intensity
