This circuit is based on a regulator component that consists of a transistor and zener in the same package. The circuit can be designed with the equivalent discrete configuration. The current is 200mA.
We found this circuit very simple in an old documentation. The relay is high voltage sensitive, but...
This circuit was found in an Elektor from the 90s. The circuit uses common components even today,...
The circuit, shown in figure 2, is a monostable multivibrator with two NAND ports out of the 4...