This circuit is from a Motorola documentation from 1968. The integrated one is an operational of the time still in metallic casing. Modern equivalents can be used.
Found in American documentation from the 1970s, this circuit employs an integrated circuit from...
This circuit was obtained in the publication 101 Electronics Projects of 1979. The circuit can be...
This assembly circuit using a small motor as a generator was found in Radio Electroics magazine from...