This circuit was found in a Poptronics of the 90's. The components can be changed to the desired frequency. The power supply must be symmetrical.
This circuit for high-impedance magnetic headphones was suggested as an experimental amplifier for hearing...
This circuit, obtained from the component manual used, has an ultra narrow 1 kHz range given by...
In this circuit the 555 is configured as an adjustable timer for long intervals. The capacitor C1 can be...