We found this circuit in the September 1971 issue of Radio Electronics magazine. The sensor is an LDR and R1 adjusts the sensitivity. A relay with the appropriate voltage can be used instead of a buzzer.
Operatives used in this 80's configuration are not common today, but it is valid for modern...
The 5 outputs of the internal 4018 integrated flop flops can be used simultaneously for the...
This voltage-controlled potentiometer using an LDR was found in an English documentation. LDR is...