This static switch or triac contactor was obtained from Philips 1969 documentation. The SCR is from the era, but modern equivalents depending on the load can be used.
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...