Another of the many tachometer circuits we have on our site. This one is from the September 1976 Radio Elecronics magazine. The circuit is connected to the platinum contacts of a car or to a sensor.
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...