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 circuit is from an English publication from 1965. The transistors used are rare, however, they...
This low voltage circuit was found in the November 1960 Radio Electronics magazine announcing new...
We found this circuit in a 2003 publication. The indicated coil is for capturing the signals in an...