We found this circuit in a 1996 publication. The circuit uses components that are still common. The timing depends on C1, which can be changed, and the triac can be of any type.
This 100 Hz filter was found in the August 1993 issue of Electronics Now. The components can be...
Found in an Elektor from the 90s, this circuit can be powered directly by the power grid. The...
The power supply for this circuit found in a QST magazine is given in the previous circuit. The...