Found in American documentation from the 90s, this circuit can be applied to other operational ones. We found it in an EDN of the time. Next to the diagram is the response curve.
This circuit can measure frequencies up to just over 1 MHz and uses CMOS technology. The circuit is...
This circuit, found in 2002 documentation, generates a strong audio tone when the light in the...
The integrated circuit used in this 80's application is not common today. However, modern...