We found this configuration in a 1990 Poptronics. The circuit can be powered by voltages between 6 and 15 V, changing the resistors in series with the LED. The frequency is set at R7.
The XR2206 is not a common component today, but if you have one you can build this function...
This circuit was found in Philips documentation from 1967. The components are of the time, being...
The proposed circuit generates signals in the range between 9 kHz and more than 44 kHz, which, it is...