We found this circuit in the November 1992 issue of Radio Electronics magazine. The circuit has two integrated circuits, one of which is a preamplifier stage. The power supply must be dual.
Found in a 1964 CQ magazine this circuit consists of an automatic telegraphic key, providing the...
Found in a 1967 American electronics magazine, this circuit has an input impedance of 2000 ohms....
This circuit can generate signals from 80 to 800 Hz with an amplitude of 0.3 V. We find it in a...