This circuit generates sinusoidal signals between 300 and 3000 Hz. We find a 303 Circuits from the 90's. The operational ones are types with FET. The power supply must be symmetrical.
This is a Philips commercial circuit from the 1980s. The circuit must be powered by 28 V and its...
This circuit can serve as a basis for a digital mixer or simply for a noiseless switch of audio...
This circuit was found in a 1980s documentation. The IC is the 7400 and should be powered with 5...