This is a typical point scale or moving bar circuit with the LM3915. We found it in old American documentation. The operational amplifier supports an equivalent modern type.
The component used, which is not common today, is an electronic attenuator. In this application of the...
Found in Analog Devices documentation, this circuit uses components from the time. Formulas for...
This circuit was found in a Radio Electronics magazine from October 1987. It can be used as a...