Picture of DARK/LIGHT SENSOR BASED ON  the LM741 opamp
hey everybody,i'm going to make a dark /light sensor using a lm741 opamp .It is very easy and requires only very few parts and is quite interesting .read on.

questions for the instructables make to learn youth contest :
what did you make?
-i made a light/dark sensor based on the LM741 opamp using parts from my local electronic store.

how did you make it?
- i got the idea from a video about making a dark /light sensor using arduino,so i decided to make an easier version of it.

where did you make it?
-i made it at my school and entered it for my science fair.

what did you learn?
- i learnt how a op amp works and how to use it and all the cool circuits you can do using it.
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-100k resistor x2
-4.7k resistor x1 
-photo resistor x1
-180 ohm resistor(i did'nt put a picture for this)
-lm741 opamp ic
-l.e.d(any color) x1
-jumper wires
-9v battery 
-9v battery snap and
- a breadboard

Strontium (author) 2 years ago
I have entered the Make to learn youth contest.Please vote for me and comment on my instructable. Thank you for viewing.
rebaz.physics2 months ago

waw this circuit work for me =D =D thanks bro


may i ask? why do you have extra 2 resistor at pin 2 and 3 twisting tgt? my circuit can work but my led still light up when i close up photoresistor

samzie29211 months ago

this circuit doesnt work for me.. help needed

samzie29211 months ago

this circuit doesnt work for me.. help needed

pfred22 years ago
What contest have you entered this into? I might vote for you if I could see it.