Using the 741 this circuit can be adjusted to values between 1 Hz and 100 kHz. The power supply must be symmetrical. We found it in the Radio Electronics magazine of November 1973.
This circuit was found in a 1987 edition of the United States' Hands On Electronics magazine. The...
The circuit presented is quite simple, employing tone modulation of the signal. To receive the...
This circuit was obtained in an old American documentation. The integrated circuit used is...