This circuit with germanium transistors is from 1960 and was found in Mullard's transistor application manual from 1960. The circuit can be adapted to use more modern transistors.
This circuit was found in National Semiconductor documentation from the 90s. The circuit uses two...
We found this circuit in the March 1984 issue of Radio Electronics magazine. The module used is a...
This circuit was obtained in an old Elektor and can be adapted to use white power LEDs. The...