Automatic night light.

The function of the circuit is to turn on a light bulb when its dark enough and turn it off when its dark enough, depending on the upper and lower threshold. The upper and lower threshold voltage are independent with each other. With the use of doides we can prevent the flow of current that affects the voltage threshold voltage which is set by the two potentiometers. We connect a 100k ohm resistor to forward bias the diode. the voltage we set in the potentiometer will be deducted by 0.7 V and that is the input voltage. The input voltage came from an LDR in series with the 4.7k resistor. Note :the left pot should be for lower threshold. And the right pot should be for upper threshold. Lastly, the left pot voltage should be lesser than the right one, otherwise , it would not work. Circuit designed by : Rios

published 2 years ago