This circuit activates a recorder from the signal obtained from a telephone line in the service. It is used to make automatic call recordings.
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...