Shown here is a low power consuming LED lamp circuit which starts to grow after light intensity goes below a threshold level of detection. This is not a switch [[wysiwyg_imageupload::]]based circuit, thus needs no human interference in order to turn it ON or OFF. Circuit is based on IC CA3140 which is a operational amplifier which combine the voltage of PMOS transistor with high voltage bipolar transistor on single chip, Light depending resistor(LDR) whose resistance dependent upon the amount of light falling on it and few more components. The circuit uses an operational amplifier CA3140 whose pins 2 and 3 act as inverting and non inverting inputs. Keep on reading to find out how the circuit is constructed and how it works.