This simple timer with unijunction transistor was found in an old American technical documentation. We can use 2N2646 for the unijunction and BC548 for the transistor.
This filters blocks radio interference or noise coming from the AC Power line. Noise such as the...
Found in a 90s Popular Electronics, this circuit triggers a relay in case of overvoltage. Can be used as a...
We found this sophisticated home alarm in a 1994 documentation. The circuit supports sensors of...