This circuit can be used as an amplifier for musical instruments or even with your cell phone. The circuit is old and was found in the 1990 edition of Radio Electronics Experimenter magazine.
When a pulse of light reaches the sensor [a CDs cell or LDR] the flip-flop changes its state....
This circuit is an impedance adapter. The circuit is from a Radio Electronics from April 1966. The...
This circuit was obtained in an old American documentation serving only for general purpose NPN...