Found in a 1969 Electronics World, this circuit generates low frequency signals with two repetition bands. Transistors support modern equivalents.
We found this circuit in an American publication from the 1990s. The circuit has a Darlington...
The sensor for this alarm is an LDR and it consists of an oscillator that goes into action when...
This circuit was found in a computer publication from the 1970s. The transistors can be the BD135...