This circuit provides a logic output signal when the voltage exceeds a certain value. The circuit is from the 1994 Linear Applications Handbook by National Semiconductor.
We found this measurement circuit with a logarithmic scale in an Electronics Now from November 1995....
This circuit was found in a 1986 documentation. The circuit uses 12 V relays and is powered by a...
This circuit was found in a 90s Popular Electronics. The sensors can be common speakers that reach...