This circuit was found in American documentation from the 1980s. The integrated circuit used is a voltage comparator of the time. Modern equivalents can be tested.
This circuit was found in a 1970 IEEE publication. The circuit functions as a voltage controlled...
Found in a documentation from the 90s, this circuit limits and amplifies a voice signal in the 800...
This gas sensor circuit was found in July 1976 Radio Electronics magazine. The TGS sensor was a...