This circuit with zener diodes was found in documentation from the 90s. The zener diodes determine the lighting point of the LEDs. The circuit is for 12 V automotive batteries.
We found this transistorized circuit in a 1985 documentation. The circuit can operate with...
We found this small audio amplifier in the November 1999 issue of Electronics Now magazine. The...
This low power circuit for the FM band was found in a spy book from the 90s. The tunnel diode is...