This circuit was found in a Popular Electronics from the 90s. It is intended to power the filament of old radio valves in recovery works. It is indicated for tubes that use 5 V of filament.
This circuit came out in an American magazine that no longer exists. It's the Electronic...
This circuit originally came out in a Budget Electronics from 1981. The American magazine no...
This is the traditional audio preamp configuration with the National Semiconductor LM382. The...