We found this circuit in an article that describes several alarms that are in the sequence in our section. The article is from the Radio Electronics magazine of May 1971.
We obtained this circuit from an old Argentine magazine. The circuit originally uses germanium...
We found this circuit in an old English publication. The sensor is a common LDR. and the...
This circuit is from an 80's component manual. The components are from the time, but the circuit...