We found this circuit in a Poptronics from the 90's. Equivalent operational amplifiers can be used. The circuit must be supplied by a symmetrical source.
This configuration is very traditional, appearing in several publications around the world. This...
This is the normal configuration for dividing a TTL signal by 7. The 7490 can divide by other...
Found in a 1967 Electronics World, this oscillator changes its tone when objects move in their...