This optical counter was found in a 1964 Electronics Design. It makes use of an uncommon optocoupler today, using emission lamp and a phototransistor.
This guitar pedal was found in a 2004 documentation. The signal is transmitted to an FM receiver...
This circuit uses two oscillators to produce a sound that seems the sound of a ring-bell. The...
This circuit for very long-time intervals was found in the March 1993 Radio Electronics magazine. Times...