This circuit was found in a 90s Wels' Think Tank. The frequency depends on C2 and R3. The handset or speaker must be at least 80-ohm. Observe the low supply voltage.
The circuit shown in the figure has elements for maximum gain at maximum speed. By setting the...
This circuit was found in the March 1993 issue of Electronics Now magazine. The circuit is a...
This circuit was found in documentation from the 1970s. However, it can be implemented with modern...