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.
This two-channel DC volume control uses a transconductance operational amplifier. The transistors can be...
The CMOS 4046 integrated circuit is not very common today, consisting of a very efficient PLL for...
This is the project we have described, as found in a 1981 documentation. In the figure we show the...