This small tone generator was found in the November 1987 issue of Radio Electronics magazine. The phototransistor is common and controls the sounds generated. The basic frequency is given by C1.
This circuit is from a Radio Electronics from April 1972. The circuit uses power transistors of...
We found this simple circuit in a 1999 documentation. It converts low-intensity sinusoidal signals (a...
This very high voltage circuit was found in the 1990 special issue of Radio Electronics...