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Then either the 555 is defective, or the leakage current of C2 is too high or the value of R7 is too high.cannibal said:I done the circuit
there was no timeout for 555
Maybe the 1M pot doesn't conduct.cannibal said:I replaced the C2 with new one (10uF)
the polarity connection checked correct
battrey changed to 9V
the problem still
buzzer won't stop when it get activated
audioguru said:Maybe the 1M pot doesn't conduct.
Replace the defective 555 IC.
Why ask? Simply look on the datasheet.cannibal said:after how many seconds the 555 IC should time out ??
Connect another transistor, LDR and 100k pot in the same manner as is shown in the diagram and connect the collector of the second transistor to the collector of the first.cannibal said:One more additional question
how to add extra photoresistor in this circuit
so if one of them is in drak mode then the buzzer will be activated even if the other pototransistor is in light mode