This circuit was obtained from the Encyclopedia of Electronic Circuits volume 5 of 1995. The circuit uses the 4001 CMOS to obtain hysteresis in the sensor feedback.
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...