Found in a 90’s 303 Circuits, this circuit uses components that are still common and has a common LED as indicator.
This circuit was suggested by Motorola in its manual of components for optoelectronics (1987)...
This sweep oscillator was found in 1980s American documentation and can be assembled with current...
In the figure we have a low-pass filter, with a cutoff frequency of 10 kHz, also suggested by...