Other versions exist on this site from various publications. This one is from the Radio Electronics Experimenter from 1990. The bargraph circuit uses the UAA170.
We found this amplifier circuit for inductive audio pickups in a documentation from the 70s. The...
The circuit is from Motorola's Linear Databook from 1990, but the configuration is current because...
This 6-transistor commercial radio with 6 V supply was found in a Japanese publication from the...