0 Simple Darkness Detector (indicator)

What this circuit does is LED will light up when the environment is dark thus very suitable as darkness sensor or indicator. Adjusting the potentiometer R1will adjust its sensitivity. Full scale of R1 decreases its sensitivity while setting R1 to minimum makes it very sensitive.
schematic diagram
Part List:
R1 -300 kilo ohms potentiometer or any near values
R2 - 100 ohms 1/4W
LDR - any LDR
LED - red or similar LED (see LED pinout in case you forget)
Q1 - 2N2222 or similar NPN transistor
LDR jpg
2N2222 pinout

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