Like the previous circuits, this one uses a small speaker as a microphone and has two amplification stages with 600-ohm output.
I found this circuit in an Electronics Handbook, an American publication from 1989 and that no...
Operating in the range of 1.5 to 15 kHz, this sinusoidal oscillator is based on a 741 operational. The...
This circuit produces 1 kHz square signals using the CMOS IC 4070. The frequency is given by the...